/*
 * Copyright (c) 2012, 2015, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
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/*
 *
 *
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 *
 * Copyright (c) 2008-2012, Stephen Colebourne & Michael Nascimento Santos
 *
 * All rights hg qreserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *  * Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 *
 *  * Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 *
 *  * Neither the name of JSR-310 nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
package java.time.format;

import static java.time.temporal.ChronoField.DAY_OF_MONTH;
import static java.time.temporal.ChronoField.HOUR_OF_DAY;
import static java.time.temporal.ChronoField.INSTANT_SECONDS;
import static java.time.temporal.ChronoField.MINUTE_OF_HOUR;
import static java.time.temporal.ChronoField.MONTH_OF_YEAR;
import static java.time.temporal.ChronoField.NANO_OF_SECOND;
import static java.time.temporal.ChronoField.OFFSET_SECONDS;
import static java.time.temporal.ChronoField.SECOND_OF_MINUTE;
import static java.time.temporal.ChronoField.YEAR;

import java.lang.ref.SoftReference;
import java.math.BigDecimal;
import java.math.BigInteger;
import java.math.RoundingMode;
import java.text.ParsePosition;
import java.time.DateTimeException;
import java.time.Instant;
import java.time.LocalDate;
import java.time.LocalDateTime;
import java.time.ZoneId;
import java.time.ZoneOffset;
import java.time.chrono.ChronoLocalDate;
import java.time.chrono.Chronology;
import java.time.chrono.IsoChronology;
import java.time.format.DateTimeTextProvider.LocaleStore;
import java.time.temporal.ChronoField;
import java.time.temporal.IsoFields;
import java.time.temporal.TemporalAccessor;
import java.time.temporal.TemporalField;
import java.time.temporal.TemporalQueries;
import java.time.temporal.TemporalQuery;
import java.time.temporal.ValueRange;
import java.time.temporal.WeekFields;
import java.time.zone.ZoneRulesProvider;
import java.util.AbstractMap.SimpleImmutableEntry;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.Comparator;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Objects;
import java.util.Set;
import java.util.TimeZone;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;

import sun.util.locale.provider.LocaleProviderAdapter;
import sun.util.locale.provider.LocaleResources;
import sun.util.locale.provider.TimeZoneNameUtility;

/**
 * Builder to create date-time formatters. <p> This allows a {@code DateTimeFormatter} to be
 * created. All date-time formatters are created ultimately using this builder. <p> The basic
 * elements of date-time can all be added: <ul> <li>Value - a numeric value</li> <li>Fraction - a
 * fractional value including the decimal place. Always use this when outputting fractions to ensure
 * that the fraction is parsed correctly</li> <li>Text - the textual equivalent for the value</li>
 * <li>OffsetId/Offset - the {@linkplain ZoneOffset zone offset}</li> <li>ZoneId - the {@linkplain
 * ZoneId time-zone} id</li> <li>ZoneText - the name of the time-zone</li> <li>ChronologyId - the
 * {@linkplain Chronology chronology} id</li> <li>ChronologyText - the name of the chronology</li>
 * <li>Literal - a text literal</li> <li>Nested and Optional - formats can be nested or made
 * optional</li> </ul> In addition, any of the elements may be decorated by padding, either with
 * spaces or any other character. <p> Finally, a shorthand pattern, mostly compatible with {@code
 * java.text.SimpleDateFormat SimpleDateFormat} can be used, see {@link #appendPattern(String)}. In
 * practice, this simply parses the pattern and calls other methods on the builder.
 *
 * @implSpec This class is a mutable builder intended for use from a single thread.
 * @since 1.8
 */
public final class DateTimeFormatterBuilder {

  /**
   * Query for a time-zone that is region-only.
   */
  private static final TemporalQuery<ZoneId> QUERY_REGION_ONLY = (temporal) -> {
    ZoneId zone = temporal.query(TemporalQueries.zoneId());
    return (zone != null && zone instanceof ZoneOffset == false ? zone : null);
  };

  /**
   * The currently active builder, used by the outermost builder.
   */
  private DateTimeFormatterBuilder active = this;
  /**
   * The parent builder, null for the outermost builder.
   */
  private final DateTimeFormatterBuilder parent;
  /**
   * The list of printers that will be used.
   */
  private final List<DateTimePrinterParser> printerParsers = new ArrayList<>();
  /**
   * Whether this builder produces an optional formatter.
   */
  private final boolean optional;
  /**
   * The width to pad the next field to.
   */
  private int padNextWidth;
  /**
   * The character to pad the next field with.
   */
  private char padNextChar;
  /**
   * The index of the last variable width value parser.
   */
  private int valueParserIndex = -1;

  /**
   * Gets the formatting pattern for date and time styles for a locale and chronology.
   * The locale and chronology are used to lookup the locale specific format
   * for the requested dateStyle and/or timeStyle.
   *
   * @param dateStyle the FormatStyle for the date, null for time-only pattern
   * @param timeStyle the FormatStyle for the time, null for date-only pattern
   * @param chrono the Chronology, non-null
   * @param locale the locale, non-null
   * @return the locale and Chronology specific formatting pattern
   * @throws IllegalArgumentException if both dateStyle and timeStyle are null
   */
  public static String getLocalizedDateTimePattern(FormatStyle dateStyle, FormatStyle timeStyle,
      Chronology chrono, Locale locale) {
    Objects.requireNonNull(locale, "locale");
    Objects.requireNonNull(chrono, "chrono");
    if (dateStyle == null && timeStyle == null) {
      throw new IllegalArgumentException("Either dateStyle or timeStyle must be non-null");
    }
    LocaleResources lr = LocaleProviderAdapter.getResourceBundleBased().getLocaleResources(locale);
    String pattern = lr.getJavaTimeDateTimePattern(
        convertStyle(timeStyle), convertStyle(dateStyle), chrono.getCalendarType());
    return pattern;
  }

  /**
   * Converts the given FormatStyle to the java.text.DateFormat style.
   *
   * @param style the FormatStyle style
   * @return the int style, or -1 if style is null, indicating un-required
   */
  private static int convertStyle(FormatStyle style) {
    if (style == null) {
      return -1;
    }
    return style.ordinal();  // indices happen to align
  }

  /**
   * Constructs a new instance of the builder.
   */
  public DateTimeFormatterBuilder() {
    super();
    parent = null;
    optional = false;
  }

  /**
   * Constructs a new instance of the builder.
   *
   * @param parent the parent builder, not null
   * @param optional whether the formatter is optional, not null
   */
  private DateTimeFormatterBuilder(DateTimeFormatterBuilder parent, boolean optional) {
    super();
    this.parent = parent;
    this.optional = optional;
  }

  //-----------------------------------------------------------------------

  /**
   * Changes the parse style to be case sensitive for the remainder of the formatter.
   * <p>
   * Parsing can be case sensitive or insensitive - by default it is case sensitive.
   * This method allows the case sensitivity setting of parsing to be changed.
   * <p>
   * Calling this method changes the state of the builder such that all
   * subsequent builder method calls will parse text in case sensitive mode.
   * See {@link #parseCaseInsensitive} for the opposite setting.
   * The parse case sensitive/insensitive methods may be called at any point
   * in the builder, thus the parser can swap between case parsing modes
   * multiple times during the parse.
   * <p>
   * Since the default is case sensitive, this method should only be used after
   * a previous call to {@code #parseCaseInsensitive}.
   *
   * @return this, for chaining, not null
   */
  public DateTimeFormatterBuilder parseCaseSensitive() {
    appendInternal(SettingsParser.SENSITIVE);
    return this;
  }

  /**
   * Changes the parse style to be case insensitive for the remainder of the formatter.
   * <p>
   * Parsing can be case sensitive or insensitive - by default it is case sensitive.
   * This method allows the case sensitivity setting of parsing to be changed.
   * <p>
   * Calling this method changes the state of the builder such that all
   * subsequent builder method calls will parse text in case insensitive mode.
   * See {@link #parseCaseSensitive()} for the opposite setting.
   * The parse case sensitive/insensitive methods may be called at any point
   * in the builder, thus the parser can swap between case parsing modes
   * multiple times during the parse.
   *
   * @return this, for chaining, not null
   */
  public DateTimeFormatterBuilder parseCaseInsensitive() {
    appendInternal(SettingsParser.INSENSITIVE);
    return this;
  }

  //-----------------------------------------------------------------------

  /**
   * Changes the parse style to be strict for the remainder of the formatter.
   * <p>
   * Parsing can be strict or lenient - by default its strict.
   * This controls the degree of flexibility in matching the text and sign styles.
   * <p>
   * When used, this method changes the parsing to be strict from this point onwards.
   * As strict is the default, this is normally only needed after calling {@link #parseLenient()}.
   * The change will remain in force until the end of the formatter that is eventually
   * constructed or until {@code parseLenient} is called.
   *
   * @return this, for chaining, not null
   */
  public DateTimeFormatterBuilder parseStrict() {
    appendInternal(SettingsParser.STRICT);
    return this;
  }

  /**
   * Changes the parse style to be lenient for the remainder of the formatter.
   * Note that case sensitivity is set separately to this method.
   * <p>
   * Parsing can be strict or lenient - by default its strict.
   * This controls the degree of flexibility in matching the text and sign styles.
   * Applications calling this method should typically also call {@link #parseCaseInsensitive()}.
   * <p>
   * When used, this method changes the parsing to be lenient from this point onwards.
   * The change will remain in force until the end of the formatter that is eventually
   * constructed or until {@code parseStrict} is called.
   *
   * @return this, for chaining, not null
   */
  public DateTimeFormatterBuilder parseLenient() {
    appendInternal(SettingsParser.LENIENT);
    return this;
  }

  //-----------------------------------------------------------------------

  /**
   * Appends a default value for a field to the formatter for use in parsing.
   * <p>
   * This appends an instruction to the builder to inject a default value
   * into the parsed result. This is especially useful in conjunction with
   * optional parts of the formatter.
   * <p>
   * For example, consider a formatter that parses the year, followed by
   * an optional month, with a further optional day-of-month. Using such a
   * formatter would require the calling code to check whether a full date,
   * year-month or just a year had been parsed. This method can be used to
   * default the month and day-of-month to a sensible value, such as the
   * first of the month, allowing the calling code to always get a date.
   * <p>
   * During formatting, this method has no effect.
   * <p>
   * During parsing, the current state of the parse is inspected.
   * If the specified field has no associated value, because it has not been
   * parsed successfully at that point, then the specified value is injected
   * into the parse result. Injection is immediate, thus the field-value pair
   * will be visible to any subsequent elements in the formatter.
   * As such, this method is normally called at the end of the builder.
   *
   * @param field the field to default the value of, not null
   * @param value the value to default the field to
   * @return this, for chaining, not null
   */
  public DateTimeFormatterBuilder parseDefaulting(TemporalField field, long value) {
    Objects.requireNonNull(field, "field");
    appendInternal(new DefaultValueParser(field, value));
    return this;
  }

  //-----------------------------------------------------------------------

  /**
   * Appends the value of a date-time field to the formatter using a normal
   * output style.
   * <p>
   * The value of the field will be output during a format.
   * If the value cannot be obtained then an exception will be thrown.
   * <p>
   * The value will be printed as per the normal format of an integer value.
   * Only negative numbers will be signed. No padding will be added.
   * <p>
   * The parser for a variable width value such as this normally behaves greedily,
   * requiring one digit, but accepting as many digits as possible.
   * This behavior can be affected by 'adjacent value parsing'.
   * See {@link #appendValue(java.time.temporal.TemporalField, int)} for full details.
   *
   * @param field the field to append, not null
   * @return this, for chaining, not null
   */
  public DateTimeFormatterBuilder appendValue(TemporalField field) {
    Objects.requireNonNull(field, "field");
    appendValue(new NumberPrinterParser(field, 1, 19, SignStyle.NORMAL));
    return this;
  }

  /**
   * Appends the value of a date-time field to the formatter using a fixed width, zero-padded
   * approach. <p> The value of the field will be output during a format. If the value cannot be
   * obtained then an exception will be thrown. <p> The value will be zero-padded on the left. If
   * the size of the value means that it cannot be printed within the width then an exception is
   * thrown. If the value of the field is negative then an exception is thrown during formatting.
   * <p> This method supports a special technique of parsing known as 'adjacent value parsing'. This
   * technique solves the problem where a value, variable or fixed width, is followed by one or more
   * fixed length values. The standard parser is greedy, and thus it would normally steal the digits
   * that are needed by the fixed width value parsers that follow the variable width one. <p> No
   * action is required to initiate 'adjacent value parsing'. When a call to {@code appendValue} is
   * made, the builder enters adjacent value parsing setup mode. If the immediately subsequent
   * method call or calls on the same builder are for a fixed width value, then the parser will
   * reserve space so that the fixed width values can be parsed. <p> For example, consider {@code
   * builder.appendValue(YEAR).appendValue(MONTH_OF_YEAR, 2);} The year is a variable width parse of
   * between 1 and 19 digits. The month is a fixed width parse of 2 digits. Because these were
   * appended to the same builder immediately after one another, the year parser will reserve two
   * digits for the month to parse. Thus, the text '201106' will correctly parse to a year of 2011
   * and a month of 6. Without adjacent value parsing, the year would greedily parse all six digits
   * and leave nothing for the month. <p> Adjacent value parsing applies to each set of fixed width
   * not-negative values in the parser that immediately follow any kind of value, variable or fixed
   * width. Calling any other append method will end the setup of adjacent value parsing. Thus, in
   * the unlikely event that you need to avoid adjacent value parsing behavior, simply add the
   * {@code appendValue} to another {@code DateTimeFormatterBuilder} and add that to this builder.
   * <p> If adjacent parsing is active, then parsing must match exactly the specified number of
   * digits in both strict and lenient modes. In addition, no positive or negative sign is
   * permitted.
   *
   * @param field the field to append, not null
   * @param width the width of the printed field, from 1 to 19
   * @return this, for chaining, not null
   * @throws IllegalArgumentException if the width is invalid
   */
  public DateTimeFormatterBuilder appendValue(TemporalField field, int width) {
    Objects.requireNonNull(field, "field");
    if (width < 1 || width > 19) {
      throw new IllegalArgumentException(
          "The width must be from 1 to 19 inclusive but was " + width);
    }
    NumberPrinterParser pp = new NumberPrinterParser(field, width, width, SignStyle.NOT_NEGATIVE);
    appendValue(pp);
    return this;
  }

  /**
   * Appends the value of a date-time field to the formatter providing full
   * control over formatting.
   * <p>
   * The value of the field will be output during a format.
   * If the value cannot be obtained then an exception will be thrown.
   * <p>
   * This method provides full control of the numeric formatting, including
   * zero-padding and the positive/negative sign.
   * <p>
   * The parser for a variable width value such as this normally behaves greedily,
   * accepting as many digits as possible.
   * This behavior can be affected by 'adjacent value parsing'.
   * See {@link #appendValue(java.time.temporal.TemporalField, int)} for full details.
   * <p>
   * In strict parsing mode, the minimum number of parsed digits is {@code minWidth}
   * and the maximum is {@code maxWidth}.
   * In lenient parsing mode, the minimum number of parsed digits is one
   * and the maximum is 19 (except as limited by adjacent value parsing).
   * <p>
   * If this method is invoked with equal minimum and maximum widths and a sign style of
   * {@code NOT_NEGATIVE} then it delegates to {@code appendValue(TemporalField,int)}.
   * In this scenario, the formatting and parsing behavior described there occur.
   *
   * @param field the field to append, not null
   * @param minWidth the minimum field width of the printed field, from 1 to 19
   * @param maxWidth the maximum field width of the printed field, from 1 to 19
   * @param signStyle the positive/negative output style, not null
   * @return this, for chaining, not null
   * @throws IllegalArgumentException if the widths are invalid
   */
  public DateTimeFormatterBuilder appendValue(
      TemporalField field, int minWidth, int maxWidth, SignStyle signStyle) {
    if (minWidth == maxWidth && signStyle == SignStyle.NOT_NEGATIVE) {
      return appendValue(field, maxWidth);
    }
    Objects.requireNonNull(field, "field");
    Objects.requireNonNull(signStyle, "signStyle");
    if (minWidth < 1 || minWidth > 19) {
      throw new IllegalArgumentException(
          "The minimum width must be from 1 to 19 inclusive but was " + minWidth);
    }
    if (maxWidth < 1 || maxWidth > 19) {
      throw new IllegalArgumentException(
          "The maximum width must be from 1 to 19 inclusive but was " + maxWidth);
    }
    if (maxWidth < minWidth) {
      throw new IllegalArgumentException(
          "The maximum width must exceed or equal the minimum width but " +
              maxWidth + " < " + minWidth);
    }
    NumberPrinterParser pp = new NumberPrinterParser(field, minWidth, maxWidth, signStyle);
    appendValue(pp);
    return this;
  }

  //-----------------------------------------------------------------------

  /**
   * Appends the reduced value of a date-time field to the formatter. <p> Since fields such as year
   * vary by chronology, it is recommended to use the {@link #appendValueReduced(TemporalField, int,
   * int, ChronoLocalDate)} date} variant of this method in most cases. This variant is suitable for
   * simple fields or working with only the ISO chronology. <p> For formatting, the {@code width}
   * and {@code maxWidth} are used to determine the number of characters to format. If they are
   * equal then the format is fixed width. If the value of the field is within the range of the
   * {@code baseValue} using {@code width} characters then the reduced value is formatted otherwise
   * the value is truncated to fit {@code maxWidth}. The rightmost characters are output to match
   * the width, left padding with zero. <p> For strict parsing, the number of characters allowed by
   * {@code width} to {@code maxWidth} are parsed. For lenient parsing, the number of characters
   * must be at least 1 and less than 10. If the number of digits parsed is equal to {@code width}
   * and the value is positive, the value of the field is computed to be the first number greater
   * than or equal to the {@code baseValue} with the same least significant characters, otherwise
   * the value parsed is the field value. This allows a reduced value to be entered for values in
   * range of the baseValue and width and absolute values can be entered for values outside the
   * range. <p> For example, a base value of {@code 1980} and a width of {@code 2} will have valid
   * values from {@code 1980} to {@code 2079}. During parsing, the text {@code "12"} will result in
   * the value {@code 2012} as that is the value within the range where the last two characters are
   * "12". By contrast, parsing the text {@code "1915"} will result in the value {@code 1915}.
   *
   * @param field the field to append, not null
   * @param width the field width of the printed and parsed field, from 1 to 10
   * @param maxWidth the maximum field width of the printed field, from 1 to 10
   * @param baseValue the base value of the range of valid values
   * @return this, for chaining, not null
   * @throws IllegalArgumentException if the width or base value is invalid
   */
  public DateTimeFormatterBuilder appendValueReduced(TemporalField field,
      int width, int maxWidth, int baseValue) {
    Objects.requireNonNull(field, "field");
    ReducedPrinterParser pp = new ReducedPrinterParser(field, width, maxWidth, baseValue, null);
    appendValue(pp);
    return this;
  }

  /**
   * Appends the reduced value of a date-time field to the formatter. <p> This is typically used for
   * formatting and parsing a two digit year. <p> The base date is used to calculate the full value
   * during parsing. For example, if the base date is 1950-01-01 then parsed values for a two digit
   * year parse will be in the range 1950-01-01 to 2049-12-31. Only the year would be extracted from
   * the date, thus a base date of 1950-08-25 would also parse to the range 1950-01-01 to
   * 2049-12-31. This behavior is necessary to support fields such as week-based-year or other
   * calendar systems where the parsed value does not align with standard ISO years. <p> The exact
   * behavior is as follows. Parse the full set of fields and determine the effective chronology
   * using the last chronology if it appears more than once. Then convert the base date to the
   * effective chronology. Then extract the specified field from the chronology-specific base date
   * and use it to determine the {@code baseValue} used below. <p> For formatting, the {@code width}
   * and {@code maxWidth} are used to determine the number of characters to format. If they are
   * equal then the format is fixed width. If the value of the field is within the range of the
   * {@code baseValue} using {@code width} characters then the reduced value is formatted otherwise
   * the value is truncated to fit {@code maxWidth}. The rightmost characters are output to match
   * the width, left padding with zero. <p> For strict parsing, the number of characters allowed by
   * {@code width} to {@code maxWidth} are parsed. For lenient parsing, the number of characters
   * must be at least 1 and less than 10. If the number of digits parsed is equal to {@code width}
   * and the value is positive, the value of the field is computed to be the first number greater
   * than or equal to the {@code baseValue} with the same least significant characters, otherwise
   * the value parsed is the field value. This allows a reduced value to be entered for values in
   * range of the baseValue and width and absolute values can be entered for values outside the
   * range. <p> For example, a base value of {@code 1980} and a width of {@code 2} will have valid
   * values from {@code 1980} to {@code 2079}. During parsing, the text {@code "12"} will result in
   * the value {@code 2012} as that is the value within the range where the last two characters are
   * "12". By contrast, parsing the text {@code "1915"} will result in the value {@code 1915}.
   *
   * @param field the field to append, not null
   * @param width the field width of the printed and parsed field, from 1 to 10
   * @param maxWidth the maximum field width of the printed field, from 1 to 10
   * @param baseDate the base date used to calculate the base value for the range of valid values in
   * the parsed chronology, not null
   * @return this, for chaining, not null
   * @throws IllegalArgumentException if the width or base value is invalid
   */
  public DateTimeFormatterBuilder appendValueReduced(
      TemporalField field, int width, int maxWidth, ChronoLocalDate baseDate) {
    Objects.requireNonNull(field, "field");
    Objects.requireNonNull(baseDate, "baseDate");
    ReducedPrinterParser pp = new ReducedPrinterParser(field, width, maxWidth, 0, baseDate);
    appendValue(pp);
    return this;
  }

  /**
   * Appends a fixed or variable width printer-parser handling adjacent value mode.
   * If a PrinterParser is not active then the new PrinterParser becomes
   * the active PrinterParser.
   * Otherwise, the active PrinterParser is modified depending on the new PrinterParser.
   * If the new PrinterParser is fixed width and has sign style {@code NOT_NEGATIVE}
   * then its width is added to the active PP and
   * the new PrinterParser is forced to be fixed width.
   * If the new PrinterParser is variable width, the active PrinterParser is changed
   * to be fixed width and the new PrinterParser becomes the active PP.
   *
   * @param pp the printer-parser, not null
   * @return this, for chaining, not null
   */
  private DateTimeFormatterBuilder appendValue(NumberPrinterParser pp) {
    if (active.valueParserIndex >= 0) {
      final int activeValueParser = active.valueParserIndex;

      // adjacent parsing mode, update setting in previous parsers
      NumberPrinterParser basePP = (NumberPrinterParser) active.printerParsers
          .get(activeValueParser);
      if (pp.minWidth == pp.maxWidth && pp.signStyle == SignStyle.NOT_NEGATIVE) {
        // Append the width to the subsequentWidth of the active parser
        basePP = basePP.withSubsequentWidth(pp.maxWidth);
        // Append the new parser as a fixed width
        appendInternal(pp.withFixedWidth());
        // Retain the previous active parser
        active.valueParserIndex = activeValueParser;
      } else {
        // Modify the active parser to be fixed width
        basePP = basePP.withFixedWidth();
        // The new parser becomes the mew active parser
        active.valueParserIndex = appendInternal(pp);
      }
      // Replace the modified parser with the updated one
      active.printerParsers.set(activeValueParser, basePP);
    } else {
      // The new Parser becomes the active parser
      active.valueParserIndex = appendInternal(pp);
    }
    return this;
  }

  //-----------------------------------------------------------------------

  /**
   * Appends the fractional value of a date-time field to the formatter.
   * <p>
   * The fractional value of the field will be output including the
   * preceding decimal point. The preceding value is not output.
   * For example, the second-of-minute value of 15 would be output as {@code .25}.
   * <p>
   * The width of the printed fraction can be controlled. Setting the
   * minimum width to zero will cause no output to be generated.
   * The printed fraction will have the minimum width necessary between
   * the minimum and maximum widths - trailing zeroes are omitted.
   * No rounding occurs due to the maximum width - digits are simply dropped.
   * <p>
   * When parsing in strict mode, the number of parsed digits must be between
   * the minimum and maximum width. When parsing in lenient mode, the minimum
   * width is considered to be zero and the maximum is nine.
   * <p>
   * If the value cannot be obtained then an exception will be thrown.
   * If the value is negative an exception will be thrown.
   * If the field does not have a fixed set of valid values then an
   * exception will be thrown.
   * If the field value in the date-time to be printed is invalid it
   * cannot be printed and an exception will be thrown.
   *
   * @param field the field to append, not null
   * @param minWidth the minimum width of the field excluding the decimal point, from 0 to 9
   * @param maxWidth the maximum width of the field excluding the decimal point, from 1 to 9
   * @param decimalPoint whether to output the localized decimal point symbol
   * @return this, for chaining, not null
   * @throws IllegalArgumentException if the field has a variable set of valid values or either
   * width is invalid
   */
  public DateTimeFormatterBuilder appendFraction(
      TemporalField field, int minWidth, int maxWidth, boolean decimalPoint) {
    appendInternal(new FractionPrinterParser(field, minWidth, maxWidth, decimalPoint));
    return this;
  }

  //-----------------------------------------------------------------------

  /**
   * Appends the text of a date-time field to the formatter using the full
   * text style.
   * <p>
   * The text of the field will be output during a format.
   * The value must be within the valid range of the field.
   * If the value cannot be obtained then an exception will be thrown.
   * If the field has no textual representation, then the numeric value will be used.
   * <p>
   * The value will be printed as per the normal format of an integer value.
   * Only negative numbers will be signed. No padding will be added.
   *
   * @param field the field to append, not null
   * @return this, for chaining, not null
   */
  public DateTimeFormatterBuilder appendText(TemporalField field) {
    return appendText(field, TextStyle.FULL);
  }

  /**
   * Appends the text of a date-time field to the formatter.
   * <p>
   * The text of the field will be output during a format.
   * The value must be within the valid range of the field.
   * If the value cannot be obtained then an exception will be thrown.
   * If the field has no textual representation, then the numeric value will be used.
   * <p>
   * The value will be printed as per the normal format of an integer value.
   * Only negative numbers will be signed. No padding will be added.
   *
   * @param field the field to append, not null
   * @param textStyle the text style to use, not null
   * @return this, for chaining, not null
   */
  public DateTimeFormatterBuilder appendText(TemporalField field, TextStyle textStyle) {
    Objects.requireNonNull(field, "field");
    Objects.requireNonNull(textStyle, "textStyle");
    appendInternal(new TextPrinterParser(field, textStyle, DateTimeTextProvider.getInstance()));
    return this;
  }

  /**
   * Appends the text of a date-time field to the formatter using the specified
   * map to supply the text.
   * <p>
   * The standard text outputting methods use the localized text in the JDK.
   * This method allows that text to be specified directly.
   * The supplied map is not validated by the builder to ensure that formatting or
   * parsing is possible, thus an invalid map may throw an error during later use.
   * <p>
   * Supplying the map of text provides considerable flexibility in formatting and parsing.
   * For example, a legacy application might require or supply the months of the
   * year as "JNY", "FBY", "MCH" etc. These do not match the standard set of text
   * for localized month names. Using this method, a map can be created which
   * defines the connection between each value and the text:
   * <pre>
   * Map&lt;Long, String&gt; map = new HashMap&lt;&gt;();
   * map.put(1L, "JNY");
   * map.put(2L, "FBY");
   * map.put(3L, "MCH");
   * ...
   * builder.appendText(MONTH_OF_YEAR, map);
   * </pre>
   * <p>
   * Other uses might be to output the value with a suffix, such as "1st", "2nd", "3rd",
   * or as Roman numerals "I", "II", "III", "IV".
   * <p>
   * During formatting, the value is obtained and checked that it is in the valid range.
   * If text is not available for the value then it is output as a number.
   * During parsing, the parser will match against the map of text and numeric values.
   *
   * @param field the field to append, not null
   * @param textLookup the map from the value to the text
   * @return this, for chaining, not null
   */
  public DateTimeFormatterBuilder appendText(TemporalField field, Map<Long, String> textLookup) {
    Objects.requireNonNull(field, "field");
    Objects.requireNonNull(textLookup, "textLookup");
    Map<Long, String> copy = new LinkedHashMap<>(textLookup);
    Map<TextStyle, Map<Long, String>> map = Collections.singletonMap(TextStyle.FULL, copy);
    final LocaleStore store = new LocaleStore(map);
    DateTimeTextProvider provider = new DateTimeTextProvider() {
      @Override
      public String getText(TemporalField field, long value, TextStyle style, Locale locale) {
        return store.getText(value, style);
      }

      @Override
      public Iterator<Entry<String, Long>> getTextIterator(TemporalField field, TextStyle style,
          Locale locale) {
        return store.getTextIterator(style);
      }
    };
    appendInternal(new TextPrinterParser(field, TextStyle.FULL, provider));
    return this;
  }

  //-----------------------------------------------------------------------

  /**
   * Appends an instant using ISO-8601 to the formatter, formatting fractional
   * digits in groups of three.
   * <p>
   * Instants have a fixed output format.
   * They are converted to a date-time with a zone-offset of UTC and formatted
   * using the standard ISO-8601 format.
   * With this method, formatting nano-of-second outputs zero, three, six
   * or nine digits digits as necessary.
   * The localized decimal style is not used.
   * <p>
   * The instant is obtained using {@link ChronoField#INSTANT_SECONDS INSTANT_SECONDS}
   * and optionally (@code NANO_OF_SECOND). The value of {@code INSTANT_SECONDS}
   * may be outside the maximum range of {@code LocalDateTime}.
   * <p>
   * The {@linkplain ResolverStyle resolver style} has no effect on instant parsing.
   * The end-of-day time of '24:00' is handled as midnight at the start of the following day.
   * The leap-second time of '23:59:59' is handled to some degree, see
   * {@link DateTimeFormatter#parsedLeapSecond()} for full details.
   * <p>
   * An alternative to this method is to format/parse the instant as a single
   * epoch-seconds value. That is achieved using {@code appendValue(INSTANT_SECONDS)}.
   *
   * @return this, for chaining, not null
   */
  public DateTimeFormatterBuilder appendInstant() {
    appendInternal(new InstantPrinterParser(-2));
    return this;
  }

  /**
   * Appends an instant using ISO-8601 to the formatter with control over
   * the number of fractional digits.
   * <p>
   * Instants have a fixed output format, although this method provides some
   * control over the fractional digits. They are converted to a date-time
   * with a zone-offset of UTC and printed using the standard ISO-8601 format.
   * The localized decimal style is not used.
   * <p>
   * The {@code fractionalDigits} parameter allows the output of the fractional
   * second to be controlled. Specifying zero will cause no fractional digits
   * to be output. From 1 to 9 will output an increasing number of digits, using
   * zero right-padding if necessary. The special value -1 is used to output as
   * many digits as necessary to avoid any trailing zeroes.
   * <p>
   * When parsing in strict mode, the number of parsed digits must match the
   * fractional digits. When parsing in lenient mode, any number of fractional
   * digits from zero to nine are accepted.
   * <p>
   * The instant is obtained using {@link ChronoField#INSTANT_SECONDS INSTANT_SECONDS}
   * and optionally (@code NANO_OF_SECOND). The value of {@code INSTANT_SECONDS}
   * may be outside the maximum range of {@code LocalDateTime}.
   * <p>
   * The {@linkplain ResolverStyle resolver style} has no effect on instant parsing.
   * The end-of-day time of '24:00' is handled as midnight at the start of the following day.
   * The leap-second time of '23:59:60' is handled to some degree, see
   * {@link DateTimeFormatter#parsedLeapSecond()} for full details.
   * <p>
   * An alternative to this method is to format/parse the instant as a single
   * epoch-seconds value. That is achieved using {@code appendValue(INSTANT_SECONDS)}.
   *
   * @param fractionalDigits the number of fractional second digits to format with, from 0 to 9, or
   * -1 to use as many digits as necessary
   * @return this, for chaining, not null
   */
  public DateTimeFormatterBuilder appendInstant(int fractionalDigits) {
    if (fractionalDigits < -1 || fractionalDigits > 9) {
      throw new IllegalArgumentException(
          "The fractional digits must be from -1 to 9 inclusive but was " + fractionalDigits);
    }
    appendInternal(new InstantPrinterParser(fractionalDigits));
    return this;
  }

  //-----------------------------------------------------------------------

  /**
   * Appends the zone offset, such as '+01:00', to the formatter.
   * <p>
   * This appends an instruction to format/parse the offset ID to the builder.
   * This is equivalent to calling {@code appendOffset("+HH:MM:ss", "Z")}.
   *
   * @return this, for chaining, not null
   */
  public DateTimeFormatterBuilder appendOffsetId() {
    appendInternal(OffsetIdPrinterParser.INSTANCE_ID_Z);
    return this;
  }

  /**
   * Appends the zone offset, such as '+01:00', to the formatter.
   * <p>
   * This appends an instruction to format/parse the offset ID to the builder.
   * <p>
   * During formatting, the offset is obtained using a mechanism equivalent
   * to querying the temporal with {@link TemporalQueries#offset()}.
   * It will be printed using the format defined below.
   * If the offset cannot be obtained then an exception is thrown unless the
   * section of the formatter is optional.
   * <p>
   * During parsing, the offset is parsed using the format defined below.
   * If the offset cannot be parsed then an exception is thrown unless the
   * section of the formatter is optional.
   * <p>
   * The format of the offset is controlled by a pattern which must be one
   * of the following:
   * <ul>
   * <li>{@code +HH} - hour only, ignoring minute and second
   * <li>{@code +HHmm} - hour, with minute if non-zero, ignoring second, no colon
   * <li>{@code +HH:mm} - hour, with minute if non-zero, ignoring second, with colon
   * <li>{@code +HHMM} - hour and minute, ignoring second, no colon
   * <li>{@code +HH:MM} - hour and minute, ignoring second, with colon
   * <li>{@code +HHMMss} - hour and minute, with second if non-zero, no colon
   * <li>{@code +HH:MM:ss} - hour and minute, with second if non-zero, with colon
   * <li>{@code +HHMMSS} - hour, minute and second, no colon
   * <li>{@code +HH:MM:SS} - hour, minute and second, with colon
   * </ul>
   * The "no offset" text controls what text is printed when the total amount of
   * the offset fields to be output is zero.
   * Example values would be 'Z', '+00:00', 'UTC' or 'GMT'.
   * Three formats are accepted for parsing UTC - the "no offset" text, and the
   * plus and minus versions of zero defined by the pattern.
   *
   * @param pattern the pattern to use, not null
   * @param noOffsetText the text to use when the offset is zero, not null
   * @return this, for chaining, not null
   */
  public DateTimeFormatterBuilder appendOffset(String pattern, String noOffsetText) {
    appendInternal(new OffsetIdPrinterParser(pattern, noOffsetText));
    return this;
  }

  /**
   * Appends the localized zone offset, such as 'GMT+01:00', to the formatter.
   * <p>
   * This appends a localized zone offset to the builder, the format of the
   * localized offset is controlled by the specified {@link FormatStyle style}
   * to this method:
   * <ul>
   * <li>{@link TextStyle#FULL full} - formats with localized offset text, such
   * as 'GMT, 2-digit hour and minute field, optional second field if non-zero,
   * and colon.
   * <li>{@link TextStyle#SHORT short} - formats with localized offset text,
   * such as 'GMT, hour without leading zero, optional 2-digit minute and
   * second if non-zero, and colon.
   * </ul>
   * <p>
   * During formatting, the offset is obtained using a mechanism equivalent
   * to querying the temporal with {@link TemporalQueries#offset()}.
   * If the offset cannot be obtained then an exception is thrown unless the
   * section of the formatter is optional.
   * <p>
   * During parsing, the offset is parsed using the format defined above.
   * If the offset cannot be parsed then an exception is thrown unless the
   * section of the formatter is optional.
   * <p>
   *
   * @param style the format style to use, not null
   * @return this, for chaining, not null
   * @throws IllegalArgumentException if style is neither {@link TextStyle#FULL full} nor {@link
   * TextStyle#SHORT short}
   */
  public DateTimeFormatterBuilder appendLocalizedOffset(TextStyle style) {
    Objects.requireNonNull(style, "style");
    if (style != TextStyle.FULL && style != TextStyle.SHORT) {
      throw new IllegalArgumentException("Style must be either full or short");
    }
    appendInternal(new LocalizedOffsetIdPrinterParser(style));
    return this;
  }

  //-----------------------------------------------------------------------

  /**
   * Appends the time-zone ID, such as 'Europe/Paris' or '+02:00', to the formatter.
   * <p>
   * This appends an instruction to format/parse the zone ID to the builder.
   * The zone ID is obtained in a strict manner suitable for {@code ZonedDateTime}.
   * By contrast, {@code OffsetDateTime} does not have a zone ID suitable
   * for use with this method, see {@link #appendZoneOrOffsetId()}.
   * <p>
   * During formatting, the zone is obtained using a mechanism equivalent
   * to querying the temporal with {@link TemporalQueries#zoneId()}.
   * It will be printed using the result of {@link ZoneId#getId()}.
   * If the zone cannot be obtained then an exception is thrown unless the
   * section of the formatter is optional.
   * <p>
   * During parsing, the text must match a known zone or offset.
   * There are two types of zone ID, offset-based, such as '+01:30' and
   * region-based, such as 'Europe/London'. These are parsed differently.
   * If the parse starts with '+', '-', 'UT', 'UTC' or 'GMT', then the parser
   * expects an offset-based zone and will not match region-based zones.
   * The offset ID, such as '+02:30', may be at the start of the parse,
   * or prefixed by  'UT', 'UTC' or 'GMT'. The offset ID parsing is
   * equivalent to using {@link #appendOffset(String, String)} using the
   * arguments 'HH:MM:ss' and the no offset string '0'.
   * If the parse starts with 'UT', 'UTC' or 'GMT', and the parser cannot
   * match a following offset ID, then {@link ZoneOffset#UTC} is selected.
   * In all other cases, the list of known region-based zones is used to
   * find the longest available match. If no match is found, and the parse
   * starts with 'Z', then {@code ZoneOffset.UTC} is selected.
   * The parser uses the {@linkplain #parseCaseInsensitive() case sensitive} setting.
   * <p>
   * For example, the following will parse:
   * <pre>
   *   "Europe/London"           -- ZoneId.of("Europe/London")
   *   "Z"                       -- ZoneOffset.UTC
   *   "UT"                      -- ZoneId.of("UT")
   *   "UTC"                     -- ZoneId.of("UTC")
   *   "GMT"                     -- ZoneId.of("GMT")
   *   "+01:30"                  -- ZoneOffset.of("+01:30")
   *   "UT+01:30"                -- ZoneOffset.of("+01:30")
   *   "UTC+01:30"               -- ZoneOffset.of("+01:30")
   *   "GMT+01:30"               -- ZoneOffset.of("+01:30")
   * </pre>
   *
   * @return this, for chaining, not null
   * @see #appendZoneRegionId()
   */
  public DateTimeFormatterBuilder appendZoneId() {
    appendInternal(new ZoneIdPrinterParser(TemporalQueries.zoneId(), "ZoneId()"));
    return this;
  }

  /**
   * Appends the time-zone region ID, such as 'Europe/Paris', to the formatter,
   * rejecting the zone ID if it is a {@code ZoneOffset}.
   * <p>
   * This appends an instruction to format/parse the zone ID to the builder
   * only if it is a region-based ID.
   * <p>
   * During formatting, the zone is obtained using a mechanism equivalent
   * to querying the temporal with {@link TemporalQueries#zoneId()}.
   * If the zone is a {@code ZoneOffset} or it cannot be obtained then
   * an exception is thrown unless the section of the formatter is optional.
   * If the zone is not an offset, then the zone will be printed using
   * the zone ID from {@link ZoneId#getId()}.
   * <p>
   * During parsing, the text must match a known zone or offset.
   * There are two types of zone ID, offset-based, such as '+01:30' and
   * region-based, such as 'Europe/London'. These are parsed differently.
   * If the parse starts with '+', '-', 'UT', 'UTC' or 'GMT', then the parser
   * expects an offset-based zone and will not match region-based zones.
   * The offset ID, such as '+02:30', may be at the start of the parse,
   * or prefixed by  'UT', 'UTC' or 'GMT'. The offset ID parsing is
   * equivalent to using {@link #appendOffset(String, String)} using the
   * arguments 'HH:MM:ss' and the no offset string '0'.
   * If the parse starts with 'UT', 'UTC' or 'GMT', and the parser cannot
   * match a following offset ID, then {@link ZoneOffset#UTC} is selected.
   * In all other cases, the list of known region-based zones is used to
   * find the longest available match. If no match is found, and the parse
   * starts with 'Z', then {@code ZoneOffset.UTC} is selected.
   * The parser uses the {@linkplain #parseCaseInsensitive() case sensitive} setting.
   * <p>
   * For example, the following will parse:
   * <pre>
   *   "Europe/London"           -- ZoneId.of("Europe/London")
   *   "Z"                       -- ZoneOffset.UTC
   *   "UT"                      -- ZoneId.of("UT")
   *   "UTC"                     -- ZoneId.of("UTC")
   *   "GMT"                     -- ZoneId.of("GMT")
   *   "+01:30"                  -- ZoneOffset.of("+01:30")
   *   "UT+01:30"                -- ZoneOffset.of("+01:30")
   *   "UTC+01:30"               -- ZoneOffset.of("+01:30")
   *   "GMT+01:30"               -- ZoneOffset.of("+01:30")
   * </pre>
   * <p>
   * Note that this method is identical to {@code appendZoneId()} except
   * in the mechanism used to obtain the zone.
   * Note also that parsing accepts offsets, whereas formatting will never
   * produce one.
   *
   * @return this, for chaining, not null
   * @see #appendZoneId()
   */
  public DateTimeFormatterBuilder appendZoneRegionId() {
    appendInternal(new ZoneIdPrinterParser(QUERY_REGION_ONLY, "ZoneRegionId()"));
    return this;
  }

  /**
   * Appends the time-zone ID, such as 'Europe/Paris' or '+02:00', to
   * the formatter, using the best available zone ID.
   * <p>
   * This appends an instruction to format/parse the best available
   * zone or offset ID to the builder.
   * The zone ID is obtained in a lenient manner that first attempts to
   * find a true zone ID, such as that on {@code ZonedDateTime}, and
   * then attempts to find an offset, such as that on {@code OffsetDateTime}.
   * <p>
   * During formatting, the zone is obtained using a mechanism equivalent
   * to querying the temporal with {@link TemporalQueries#zone()}.
   * It will be printed using the result of {@link ZoneId#getId()}.
   * If the zone cannot be obtained then an exception is thrown unless the
   * section of the formatter is optional.
   * <p>
   * During parsing, the text must match a known zone or offset.
   * There are two types of zone ID, offset-based, such as '+01:30' and
   * region-based, such as 'Europe/London'. These are parsed differently.
   * If the parse starts with '+', '-', 'UT', 'UTC' or 'GMT', then the parser
   * expects an offset-based zone and will not match region-based zones.
   * The offset ID, such as '+02:30', may be at the start of the parse,
   * or prefixed by  'UT', 'UTC' or 'GMT'. The offset ID parsing is
   * equivalent to using {@link #appendOffset(String, String)} using the
   * arguments 'HH:MM:ss' and the no offset string '0'.
   * If the parse starts with 'UT', 'UTC' or 'GMT', and the parser cannot
   * match a following offset ID, then {@link ZoneOffset#UTC} is selected.
   * In all other cases, the list of known region-based zones is used to
   * find the longest available match. If no match is found, and the parse
   * starts with 'Z', then {@code ZoneOffset.UTC} is selected.
   * The parser uses the {@linkplain #parseCaseInsensitive() case sensitive} setting.
   * <p>
   * For example, the following will parse:
   * <pre>
   *   "Europe/London"           -- ZoneId.of("Europe/London")
   *   "Z"                       -- ZoneOffset.UTC
   *   "UT"                      -- ZoneId.of("UT")
   *   "UTC"                     -- ZoneId.of("UTC")
   *   "GMT"                     -- ZoneId.of("GMT")
   *   "+01:30"                  -- ZoneOffset.of("+01:30")
   *   "UT+01:30"                -- ZoneOffset.of("UT+01:30")
   *   "UTC+01:30"               -- ZoneOffset.of("UTC+01:30")
   *   "GMT+01:30"               -- ZoneOffset.of("GMT+01:30")
   * </pre>
   * <p>
   * Note that this method is identical to {@code appendZoneId()} except
   * in the mechanism used to obtain the zone.
   *
   * @return this, for chaining, not null
   * @see #appendZoneId()
   */
  public DateTimeFormatterBuilder appendZoneOrOffsetId() {
    appendInternal(new ZoneIdPrinterParser(TemporalQueries.zone(), "ZoneOrOffsetId()"));
    return this;
  }

  /**
   * Appends the time-zone name, such as 'British Summer Time', to the formatter.
   * <p>
   * This appends an instruction to format/parse the textual name of the zone to
   * the builder.
   * <p>
   * During formatting, the zone is obtained using a mechanism equivalent
   * to querying the temporal with {@link TemporalQueries#zoneId()}.
   * If the zone is a {@code ZoneOffset} it will be printed using the
   * result of {@link ZoneOffset#getId()}.
   * If the zone is not an offset, the textual name will be looked up
   * for the locale set in the {@link DateTimeFormatter}.
   * If the temporal object being printed represents an instant, then the text
   * will be the summer or winter time text as appropriate.
   * If the lookup for text does not find any suitable result, then the
   * {@link ZoneId#getId() ID} will be printed instead.
   * If the zone cannot be obtained then an exception is thrown unless the
   * section of the formatter is optional.
   * <p>
   * During parsing, either the textual zone name, the zone ID or the offset
   * is accepted. Many textual zone names are not unique, such as CST can be
   * for both "Central Standard Time" and "China Standard Time". In this
   * situation, the zone id will be determined by the region information from
   * formatter's  {@link DateTimeFormatter#getLocale() locale} and the standard
   * zone id for that area, for example, America/New_York for the America Eastern
   * zone. The {@link #appendZoneText(TextStyle, Set)} may be used
   * to specify a set of preferred {@link ZoneId} in this situation.
   *
   * @param textStyle the text style to use, not null
   * @return this, for chaining, not null
   */
  public DateTimeFormatterBuilder appendZoneText(TextStyle textStyle) {
    appendInternal(new ZoneTextPrinterParser(textStyle, null));
    return this;
  }

  /**
   * Appends the time-zone name, such as 'British Summer Time', to the formatter.
   * <p>
   * This appends an instruction to format/parse the textual name of the zone to
   * the builder.
   * <p>
   * During formatting, the zone is obtained using a mechanism equivalent
   * to querying the temporal with {@link TemporalQueries#zoneId()}.
   * If the zone is a {@code ZoneOffset} it will be printed using the
   * result of {@link ZoneOffset#getId()}.
   * If the zone is not an offset, the textual name will be looked up
   * for the locale set in the {@link DateTimeFormatter}.
   * If the temporal object being printed represents an instant, then the text
   * will be the summer or winter time text as appropriate.
   * If the lookup for text does not find any suitable result, then the
   * {@link ZoneId#getId() ID} will be printed instead.
   * If the zone cannot be obtained then an exception is thrown unless the
   * section of the formatter is optional.
   * <p>
   * During parsing, either the textual zone name, the zone ID or the offset
   * is accepted. Many textual zone names are not unique, such as CST can be
   * for both "Central Standard Time" and "China Standard Time". In this
   * situation, the zone id will be determined by the region information from
   * formatter's  {@link DateTimeFormatter#getLocale() locale} and the standard
   * zone id for that area, for example, America/New_York for the America Eastern
   * zone. This method also allows a set of preferred {@link ZoneId} to be
   * specified for parsing. The matched preferred zone id will be used if the
   * textural zone name being parsed is not unique.
   * <p>
   * If the zone cannot be parsed then an exception is thrown unless the
   * section of the formatter is optional.
   *
   * @param textStyle the text style to use, not null
   * @param preferredZones the set of preferred zone ids, not null
   * @return this, for chaining, not null
   */
  public DateTimeFormatterBuilder appendZoneText(TextStyle textStyle,
      Set<ZoneId> preferredZones) {
    Objects.requireNonNull(preferredZones, "preferredZones");
    appendInternal(new ZoneTextPrinterParser(textStyle, preferredZones));
    return this;
  }

  //-----------------------------------------------------------------------

  /**
   * Appends the chronology ID, such as 'ISO' or 'ThaiBuddhist', to the formatter.
   * <p>
   * This appends an instruction to format/parse the chronology ID to the builder.
   * <p>
   * During formatting, the chronology is obtained using a mechanism equivalent
   * to querying the temporal with {@link TemporalQueries#chronology()}.
   * It will be printed using the result of {@link Chronology#getId()}.
   * If the chronology cannot be obtained then an exception is thrown unless the
   * section of the formatter is optional.
   * <p>
   * During parsing, the chronology is parsed and must match one of the chronologies
   * in {@link Chronology#getAvailableChronologies()}.
   * If the chronology cannot be parsed then an exception is thrown unless the
   * section of the formatter is optional.
   * The parser uses the {@linkplain #parseCaseInsensitive() case sensitive} setting.
   *
   * @return this, for chaining, not null
   */
  public DateTimeFormatterBuilder appendChronologyId() {
    appendInternal(new ChronoPrinterParser(null));
    return this;
  }

  /**
   * Appends the chronology name to the formatter.
   * <p>
   * The calendar system name will be output during a format.
   * If the chronology cannot be obtained then an exception will be thrown.
   *
   * @param textStyle the text style to use, not null
   * @return this, for chaining, not null
   */
  public DateTimeFormatterBuilder appendChronologyText(TextStyle textStyle) {
    Objects.requireNonNull(textStyle, "textStyle");
    appendInternal(new ChronoPrinterParser(textStyle));
    return this;
  }

  //-----------------------------------------------------------------------

  /**
   * Appends a localized date-time pattern to the formatter.
   * <p>
   * This appends a localized section to the builder, suitable for outputting
   * a date, time or date-time combination. The format of the localized
   * section is lazily looked up based on four items:
   * <ul>
   * <li>the {@code dateStyle} specified to this method
   * <li>the {@code timeStyle} specified to this method
   * <li>the {@code Locale} of the {@code DateTimeFormatter}
   * <li>the {@code Chronology}, selecting the best available
   * </ul>
   * During formatting, the chronology is obtained from the temporal object
   * being formatted, which may have been overridden by
   * {@link DateTimeFormatter#withChronology(Chronology)}.
   * <p>
   * During parsing, if a chronology has already been parsed, then it is used.
   * Otherwise the default from {@code DateTimeFormatter.withChronology(Chronology)}
   * is used, with {@code IsoChronology} as the fallback.
   * <p>
   * Note that this method provides similar functionality to methods on
   * {@code DateFormat} such as {@link java.text.DateFormat#getDateTimeInstance(int, int)}.
   *
   * @param dateStyle the date style to use, null means no date required
   * @param timeStyle the time style to use, null means no time required
   * @return this, for chaining, not null
   * @throws IllegalArgumentException if both the date and time styles are null
   */
  public DateTimeFormatterBuilder appendLocalized(FormatStyle dateStyle, FormatStyle timeStyle) {
    if (dateStyle == null && timeStyle == null) {
      throw new IllegalArgumentException("Either the date or time style must be non-null");
    }
    appendInternal(new LocalizedPrinterParser(dateStyle, timeStyle));
    return this;
  }

  //-----------------------------------------------------------------------

  /**
   * Appends a character literal to the formatter.
   * <p>
   * This character will be output during a format.
   *
   * @param literal the literal to append, not null
   * @return this, for chaining, not null
   */
  public DateTimeFormatterBuilder appendLiteral(char literal) {
    appendInternal(new CharLiteralPrinterParser(literal));
    return this;
  }

  /**
   * Appends a string literal to the formatter.
   * <p>
   * This string will be output during a format.
   * <p>
   * If the literal is empty, nothing is added to the formatter.
   *
   * @param literal the literal to append, not null
   * @return this, for chaining, not null
   */
  public DateTimeFormatterBuilder appendLiteral(String literal) {
    Objects.requireNonNull(literal, "literal");
    if (literal.length() > 0) {
      if (literal.length() == 1) {
        appendInternal(new CharLiteralPrinterParser(literal.charAt(0)));
      } else {
        appendInternal(new StringLiteralPrinterParser(literal));
      }
    }
    return this;
  }

  //-----------------------------------------------------------------------

  /**
   * Appends all the elements of a formatter to the builder.
   * <p>
   * This method has the same effect as appending each of the constituent
   * parts of the formatter directly to this builder.
   *
   * @param formatter the formatter to add, not null
   * @return this, for chaining, not null
   */
  public DateTimeFormatterBuilder append(DateTimeFormatter formatter) {
    Objects.requireNonNull(formatter, "formatter");
    appendInternal(formatter.toPrinterParser(false));
    return this;
  }

  /**
   * Appends a formatter to the builder which will optionally format/parse.
   * <p>
   * This method has the same effect as appending each of the constituent
   * parts directly to this builder surrounded by an {@link #optionalStart()} and
   * {@link #optionalEnd()}.
   * <p>
   * The formatter will format if data is available for all the fields contained within it.
   * The formatter will parse if the string matches, otherwise no error is returned.
   *
   * @param formatter the formatter to add, not null
   * @return this, for chaining, not null
   */
  public DateTimeFormatterBuilder appendOptional(DateTimeFormatter formatter) {
    Objects.requireNonNull(formatter, "formatter");
    appendInternal(formatter.toPrinterParser(true));
    return this;
  }

  //-----------------------------------------------------------------------

  /**
   * Appends the elements defined by the specified pattern to the builder. <p> All letters 'A' to
   * 'Z' and 'a' to 'z' are reserved as pattern letters. The characters '#', '{' and '}' are
   * reserved for future use. The characters '[' and ']' indicate optional patterns. The following
   * pattern letters are defined:
   * <pre>
   *  Symbol  Meaning                     Presentation      Examples
   *  ------  -------                     ------------      -------
   *   G       era                         text              AD; Anno Domini; A
   *   u       year                        year              2004; 04
   *   y       year-of-era                 year              2004; 04
   *   D       day-of-year                 number            189
   *   M/L     month-of-year               number/text       7; 07; Jul; July; J
   *   d       day-of-month                number            10
   *
   *   Q/q     quarter-of-year             number/text       3; 03; Q3; 3rd quarter
   *   Y       week-based-year             year              1996; 96
   *   w       week-of-week-based-year     number            27
   *   W       week-of-month               number            4
   *   E       day-of-week                 text              Tue; Tuesday; T
   *   e/c     localized day-of-week       number/text       2; 02; Tue; Tuesday; T
   *   F       week-of-month               number            3
   *
   *   a       am-pm-of-day                text              PM
   *   h       clock-hour-of-am-pm (1-12)  number            12
   *   K       hour-of-am-pm (0-11)        number            0
   *   k       clock-hour-of-am-pm (1-24)  number            0
   *
   *   H       hour-of-day (0-23)          number            0
   *   m       minute-of-hour              number            30
   *   s       second-of-minute            number            55
   *   S       fraction-of-second          fraction          978
   *   A       milli-of-day                number            1234
   *   n       nano-of-second              number            987654321
   *   N       nano-of-day                 number            1234000000
   *
   *   V       time-zone ID                zone-id           America/Los_Angeles; Z; -08:30
   *   z       time-zone name              zone-name         Pacific Standard Time; PST
   *   O       localized zone-offset       offset-O          GMT+8; GMT+08:00; UTC-08:00;
   *   X       zone-offset 'Z' for zero    offset-X          Z; -08; -0830; -08:30; -083015;
   * -08:30:15;
   *   x       zone-offset                 offset-x          +0000; -08; -0830; -08:30; -083015;
   * -08:30:15;
   *   Z       zone-offset                 offset-Z          +0000; -0800; -08:00;
   *
   *   p       pad next                    pad modifier      1
   *
   *   '       escape for text             delimiter
   *   ''      single quote                literal           '
   *   [       optional section start
   *   ]       optional section end
   *   #       reserved for future use
   *   {       reserved for future use
   *   }       reserved for future use
   * </pre>
   * <p> The count of pattern letters determine the format. See <a href="DateTimeFormatter.html#patterns">DateTimeFormatter</a>
   * for a user-focused description of the patterns. The following tables define how the pattern
   * letters map to the builder. <p> <b>Date fields</b>: Pattern letters to output a date.
   * <pre>
   *  Pattern  Count  Equivalent builder methods
   *  -------  -----  --------------------------
   *    G       1      appendText(ChronoField.ERA, TextStyle.SHORT)
   *    GG      2      appendText(ChronoField.ERA, TextStyle.SHORT)
   *    GGG     3      appendText(ChronoField.ERA, TextStyle.SHORT)
   *    GGGG    4      appendText(ChronoField.ERA, TextStyle.FULL)
   *    GGGGG   5      appendText(ChronoField.ERA, TextStyle.NARROW)
   *
   *    u       1      appendValue(ChronoField.YEAR, 1, 19, SignStyle.NORMAL);
   *    uu      2      appendValueReduced(ChronoField.YEAR, 2, 2000);
   *    uuu     3      appendValue(ChronoField.YEAR, 3, 19, SignStyle.NORMAL);
   *    u..u    4..n   appendValue(ChronoField.YEAR, n, 19, SignStyle.EXCEEDS_PAD);
   *    y       1      appendValue(ChronoField.YEAR_OF_ERA, 1, 19, SignStyle.NORMAL);
   *    yy      2      appendValueReduced(ChronoField.YEAR_OF_ERA, 2, 2000);
   *    yyy     3      appendValue(ChronoField.YEAR_OF_ERA, 3, 19, SignStyle.NORMAL);
   *    y..y    4..n   appendValue(ChronoField.YEAR_OF_ERA, n, 19, SignStyle.EXCEEDS_PAD);
   *    Y       1      append special localized WeekFields element for numeric week-based-year
   *    YY      2      append special localized WeekFields element for reduced numeric
   * week-based-year 2 digits;
   *    YYY     3      append special localized WeekFields element for numeric week-based-year (3,
   * 19, SignStyle.NORMAL);
   *    Y..Y    4..n   append special localized WeekFields element for numeric week-based-year (n,
   * 19, SignStyle.EXCEEDS_PAD);
   *
   *    Q       1      appendValue(IsoFields.QUARTER_OF_YEAR);
   *    QQ      2      appendValue(IsoFields.QUARTER_OF_YEAR, 2);
   *    QQQ     3      appendText(IsoFields.QUARTER_OF_YEAR, TextStyle.SHORT)
   *    QQQQ    4      appendText(IsoFields.QUARTER_OF_YEAR, TextStyle.FULL)
   *    QQQQQ   5      appendText(IsoFields.QUARTER_OF_YEAR, TextStyle.NARROW)
   *    q       1      appendValue(IsoFields.QUARTER_OF_YEAR);
   *    qq      2      appendValue(IsoFields.QUARTER_OF_YEAR, 2);
   *    qqq     3      appendText(IsoFields.QUARTER_OF_YEAR, TextStyle.SHORT_STANDALONE)
   *    qqqq    4      appendText(IsoFields.QUARTER_OF_YEAR, TextStyle.FULL_STANDALONE)
   *    qqqqq   5      appendText(IsoFields.QUARTER_OF_YEAR, TextStyle.NARROW_STANDALONE)
   *
   *    M       1      appendValue(ChronoField.MONTH_OF_YEAR);
   *    MM      2      appendValue(ChronoField.MONTH_OF_YEAR, 2);
   *    MMM     3      appendText(ChronoField.MONTH_OF_YEAR, TextStyle.SHORT)
   *    MMMM    4      appendText(ChronoField.MONTH_OF_YEAR, TextStyle.FULL)
   *    MMMMM   5      appendText(ChronoField.MONTH_OF_YEAR, TextStyle.NARROW)
   *    L       1      appendValue(ChronoField.MONTH_OF_YEAR);
   *    LL      2      appendValue(ChronoField.MONTH_OF_YEAR, 2);
   *    LLL     3      appendText(ChronoField.MONTH_OF_YEAR, TextStyle.SHORT_STANDALONE)
   *    LLLL    4      appendText(ChronoField.MONTH_OF_YEAR, TextStyle.FULL_STANDALONE)
   *    LLLLL   5      appendText(ChronoField.MONTH_OF_YEAR, TextStyle.NARROW_STANDALONE)
   *
   *    w       1      append special localized WeekFields element for numeric week-of-year
   *    ww      2      append special localized WeekFields element for numeric week-of-year,
   * zero-padded
   *    W       1      append special localized WeekFields element for numeric week-of-month
   *    d       1      appendValue(ChronoField.DAY_OF_MONTH)
   *    dd      2      appendValue(ChronoField.DAY_OF_MONTH, 2)
   *    D       1      appendValue(ChronoField.DAY_OF_YEAR)
   *    DD      2      appendValue(ChronoField.DAY_OF_YEAR, 2)
   *    DDD     3      appendValue(ChronoField.DAY_OF_YEAR, 3)
   *    F       1      appendValue(ChronoField.ALIGNED_DAY_OF_WEEK_IN_MONTH)
   *    E       1      appendText(ChronoField.DAY_OF_WEEK, TextStyle.SHORT)
   *    EE      2      appendText(ChronoField.DAY_OF_WEEK, TextStyle.SHORT)
   *    EEE     3      appendText(ChronoField.DAY_OF_WEEK, TextStyle.SHORT)
   *    EEEE    4      appendText(ChronoField.DAY_OF_WEEK, TextStyle.FULL)
   *    EEEEE   5      appendText(ChronoField.DAY_OF_WEEK, TextStyle.NARROW)
   *    e       1      append special localized WeekFields element for numeric day-of-week
   *    ee      2      append special localized WeekFields element for numeric day-of-week,
   * zero-padded
   *    eee     3      appendText(ChronoField.DAY_OF_WEEK, TextStyle.SHORT)
   *    eeee    4      appendText(ChronoField.DAY_OF_WEEK, TextStyle.FULL)
   *    eeeee   5      appendText(ChronoField.DAY_OF_WEEK, TextStyle.NARROW)
   *    c       1      append special localized WeekFields element for numeric day-of-week
   *    ccc     3      appendText(ChronoField.DAY_OF_WEEK, TextStyle.SHORT_STANDALONE)
   *    cccc    4      appendText(ChronoField.DAY_OF_WEEK, TextStyle.FULL_STANDALONE)
   *    ccccc   5      appendText(ChronoField.DAY_OF_WEEK, TextStyle.NARROW_STANDALONE)
   * </pre>
   * <p> <b>Time fields</b>: Pattern letters to output a time.
   * <pre>
   *  Pattern  Count  Equivalent builder methods
   *  -------  -----  --------------------------
   *    a       1      appendText(ChronoField.AMPM_OF_DAY, TextStyle.SHORT)
   *    h       1      appendValue(ChronoField.CLOCK_HOUR_OF_AMPM)
   *    hh      2      appendValue(ChronoField.CLOCK_HOUR_OF_AMPM, 2)
   *    H       1      appendValue(ChronoField.HOUR_OF_DAY)
   *    HH      2      appendValue(ChronoField.HOUR_OF_DAY, 2)
   *    k       1      appendValue(ChronoField.CLOCK_HOUR_OF_DAY)
   *    kk      2      appendValue(ChronoField.CLOCK_HOUR_OF_DAY, 2)
   *    K       1      appendValue(ChronoField.HOUR_OF_AMPM)
   *    KK      2      appendValue(ChronoField.HOUR_OF_AMPM, 2)
   *    m       1      appendValue(ChronoField.MINUTE_OF_HOUR)
   *    mm      2      appendValue(ChronoField.MINUTE_OF_HOUR, 2)
   *    s       1      appendValue(ChronoField.SECOND_OF_MINUTE)
   *    ss      2      appendValue(ChronoField.SECOND_OF_MINUTE, 2)
   *
   *    S..S    1..n   appendFraction(ChronoField.NANO_OF_SECOND, n, n, false)
   *    A       1      appendValue(ChronoField.MILLI_OF_DAY)
   *    A..A    2..n   appendValue(ChronoField.MILLI_OF_DAY, n)
   *    n       1      appendValue(ChronoField.NANO_OF_SECOND)
   *    n..n    2..n   appendValue(ChronoField.NANO_OF_SECOND, n)
   *    N       1      appendValue(ChronoField.NANO_OF_DAY)
   *    N..N    2..n   appendValue(ChronoField.NANO_OF_DAY, n)
   * </pre>
   * <p> <b>Zone ID</b>: Pattern letters to output {@code ZoneId}.
   * <pre>
   *  Pattern  Count  Equivalent builder methods
   *  -------  -----  --------------------------
   *    VV      2      appendZoneId()
   *    z       1      appendZoneText(TextStyle.SHORT)
   *    zz      2      appendZoneText(TextStyle.SHORT)
   *    zzz     3      appendZoneText(TextStyle.SHORT)
   *    zzzz    4      appendZoneText(TextStyle.FULL)
   * </pre>
   * <p> <b>Zone offset</b>: Pattern letters to output {@code ZoneOffset}.
   * <pre>
   *  Pattern  Count  Equivalent builder methods
   *  -------  -----  --------------------------
   *    O       1      appendLocalizedOffsetPrefixed(TextStyle.SHORT);
   *    OOOO    4      appendLocalizedOffsetPrefixed(TextStyle.FULL);
   *    X       1      appendOffset("+HHmm","Z")
   *    XX      2      appendOffset("+HHMM","Z")
   *    XXX     3      appendOffset("+HH:MM","Z")
   *    XXXX    4      appendOffset("+HHMMss","Z")
   *    XXXXX   5      appendOffset("+HH:MM:ss","Z")
   *    x       1      appendOffset("+HHmm","+00")
   *    xx      2      appendOffset("+HHMM","+0000")
   *    xxx     3      appendOffset("+HH:MM","+00:00")
   *    xxxx    4      appendOffset("+HHMMss","+0000")
   *    xxxxx   5      appendOffset("+HH:MM:ss","+00:00")
   *    Z       1      appendOffset("+HHMM","+0000")
   *    ZZ      2      appendOffset("+HHMM","+0000")
   *    ZZZ     3      appendOffset("+HHMM","+0000")
   *    ZZZZ    4      appendLocalizedOffset(TextStyle.FULL);
   *    ZZZZZ   5      appendOffset("+HH:MM:ss","Z")
   * </pre>
   * <p> <b>Modifiers</b>: Pattern letters that modify the rest of the pattern:
   * <pre>
   *  Pattern  Count  Equivalent builder methods
   *  -------  -----  --------------------------
   *    [       1      optionalStart()
   *    ]       1      optionalEnd()
   *    p..p    1..n   padNext(n)
   * </pre>
   * <p> Any sequence of letters not specified above, unrecognized letter or reserved character will
   * throw an exception. Future versions may add to the set of patterns. It is recommended to use
   * single quotes around all characters that you want to output directly to ensure that future
   * changes do not break your application. <p> Note that the pattern string is similar, but not
   * identical, to {@link java.text.SimpleDateFormat SimpleDateFormat}. The pattern string is also
   * similar, but not identical, to that defined by the Unicode Common Locale Data Repository
   * (CLDR/LDML). Pattern letters 'X' and 'u' are aligned with Unicode CLDR/LDML. By contrast,
   * {@code SimpleDateFormat} uses 'u' for the numeric day of week. Pattern letters 'y' and 'Y'
   * parse years of two digits and more than 4 digits differently. Pattern letters 'n', 'A', 'N',
   * and 'p' are added. Number types will reject large numbers.
   *
   * @param pattern the pattern to add, not null
   * @return this, for chaining, not null
   * @throws IllegalArgumentException if the pattern is invalid
   */
  public DateTimeFormatterBuilder appendPattern(String pattern) {
    Objects.requireNonNull(pattern, "pattern");
    parsePattern(pattern);
    return this;
  }

  private void parsePattern(String pattern) {
    for (int pos = 0; pos < pattern.length(); pos++) {
      char cur = pattern.charAt(pos);
      if ((cur >= 'A' && cur <= 'Z') || (cur >= 'a' && cur <= 'z')) {
        int start = pos++;
        for (; pos < pattern.length() && pattern.charAt(pos) == cur; pos++) {
          ;  // short loop
        }
        int count = pos - start;
        // padding
        if (cur == 'p') {
          int pad = 0;
          if (pos < pattern.length()) {
            cur = pattern.charAt(pos);
            if ((cur >= 'A' && cur <= 'Z') || (cur >= 'a' && cur <= 'z')) {
              pad = count;
              start = pos++;
              for (; pos < pattern.length() && pattern.charAt(pos) == cur; pos++) {
                ;  // short loop
              }
              count = pos - start;
            }
          }
          if (pad == 0) {
            throw new IllegalArgumentException(
                "Pad letter 'p' must be followed by valid pad pattern: " + pattern);
          }
          padNext(pad); // pad and continue parsing
        }
        // main rules
        TemporalField field = FIELD_MAP.get(cur);
        if (field != null) {
          parseField(cur, count, field);
        } else if (cur == 'z') {
          if (count > 4) {
            throw new IllegalArgumentException("Too many pattern letters: " + cur);
          } else if (count == 4) {
            appendZoneText(TextStyle.FULL);
          } else {
            appendZoneText(TextStyle.SHORT);
          }
        } else if (cur == 'V') {
          if (count != 2) {
            throw new IllegalArgumentException("Pattern letter count must be 2: " + cur);
          }
          appendZoneId();
        } else if (cur == 'Z') {
          if (count < 4) {
            appendOffset("+HHMM", "+0000");
          } else if (count == 4) {
            appendLocalizedOffset(TextStyle.FULL);
          } else if (count == 5) {
            appendOffset("+HH:MM:ss", "Z");
          } else {
            throw new IllegalArgumentException("Too many pattern letters: " + cur);
          }
        } else if (cur == 'O') {
          if (count == 1) {
            appendLocalizedOffset(TextStyle.SHORT);
          } else if (count == 4) {
            appendLocalizedOffset(TextStyle.FULL);
          } else {
            throw new IllegalArgumentException("Pattern letter count must be 1 or 4: " + cur);
          }
        } else if (cur == 'X') {
          if (count > 5) {
            throw new IllegalArgumentException("Too many pattern letters: " + cur);
          }
          appendOffset(OffsetIdPrinterParser.PATTERNS[count + (count == 1 ? 0 : 1)], "Z");
        } else if (cur == 'x') {
          if (count > 5) {
            throw new IllegalArgumentException("Too many pattern letters: " + cur);
          }
          String zero = (count == 1 ? "+00" : (count % 2 == 0 ? "+0000" : "+00:00"));
          appendOffset(OffsetIdPrinterParser.PATTERNS[count + (count == 1 ? 0 : 1)], zero);
        } else if (cur == 'W') {
          // Fields defined by Locale
          if (count > 1) {
            throw new IllegalArgumentException("Too many pattern letters: " + cur);
          }
          appendInternal(new WeekBasedFieldPrinterParser(cur, count));
        } else if (cur == 'w') {
          // Fields defined by Locale
          if (count > 2) {
            throw new IllegalArgumentException("Too many pattern letters: " + cur);
          }
          appendInternal(new WeekBasedFieldPrinterParser(cur, count));
        } else if (cur == 'Y') {
          // Fields defined by Locale
          appendInternal(new WeekBasedFieldPrinterParser(cur, count));
        } else {
          throw new IllegalArgumentException("Unknown pattern letter: " + cur);
        }
        pos--;

      } else if (cur == '\'') {
        // parse literals
        int start = pos++;
        for (; pos < pattern.length(); pos++) {
          if (pattern.charAt(pos) == '\'') {
            if (pos + 1 < pattern.length() && pattern.charAt(pos + 1) == '\'') {
              pos++;
            } else {
              break;  // end of literal
            }
          }
        }
        if (pos >= pattern.length()) {
          throw new IllegalArgumentException(
              "Pattern ends with an incomplete string literal: " + pattern);
        }
        String str = pattern.substring(start + 1, pos);
        if (str.length() == 0) {
          appendLiteral('\'');
        } else {
          appendLiteral(str.replace("''", "'"));
        }

      } else if (cur == '[') {
        optionalStart();

      } else if (cur == ']') {
        if (active.parent == null) {
          throw new IllegalArgumentException("Pattern invalid as it contains ] without previous [");
        }
        optionalEnd();

      } else if (cur == '{' || cur == '}' || cur == '#') {
        throw new IllegalArgumentException("Pattern includes reserved character: '" + cur + "'");
      } else {
        appendLiteral(cur);
      }
    }
  }

  @SuppressWarnings("fallthrough")
  private void parseField(char cur, int count, TemporalField field) {
    boolean standalone = false;
    switch (cur) {
      case 'u':
      case 'y':
        if (count == 2) {
          appendValueReduced(field, 2, 2, ReducedPrinterParser.BASE_DATE);
        } else if (count < 4) {
          appendValue(field, count, 19, SignStyle.NORMAL);
        } else {
          appendValue(field, count, 19, SignStyle.EXCEEDS_PAD);
        }
        break;
      case 'c':
        if (count == 2) {
          throw new IllegalArgumentException("Invalid pattern \"cc\"");
        }
                /*fallthrough*/
      case 'L':
      case 'q':
        standalone = true;
                /*fallthrough*/
      case 'M':
      case 'Q':
      case 'E':
      case 'e':
        switch (count) {
          case 1:
          case 2:
            if (cur == 'c' || cur == 'e') {
              appendInternal(new WeekBasedFieldPrinterParser(cur, count));
            } else if (cur == 'E') {
              appendText(field, TextStyle.SHORT);
            } else {
              if (count == 1) {
                appendValue(field);
              } else {
                appendValue(field, 2);
              }
            }
            break;
          case 3:
            appendText(field, standalone ? TextStyle.SHORT_STANDALONE : TextStyle.SHORT);
            break;
          case 4:
            appendText(field, standalone ? TextStyle.FULL_STANDALONE : TextStyle.FULL);
            break;
          case 5:
            appendText(field, standalone ? TextStyle.NARROW_STANDALONE : TextStyle.NARROW);
            break;
          default:
            throw new IllegalArgumentException("Too many pattern letters: " + cur);
        }
        break;
      case 'a':
        if (count == 1) {
          appendText(field, TextStyle.SHORT);
        } else {
          throw new IllegalArgumentException("Too many pattern letters: " + cur);
        }
        break;
      case 'G':
        switch (count) {
          case 1:
          case 2:
          case 3:
            appendText(field, TextStyle.SHORT);
            break;
          case 4:
            appendText(field, TextStyle.FULL);
            break;
          case 5:
            appendText(field, TextStyle.NARROW);
            break;
          default:
            throw new IllegalArgumentException("Too many pattern letters: " + cur);
        }
        break;
      case 'S':
        appendFraction(NANO_OF_SECOND, count, count, false);
        break;
      case 'F':
        if (count == 1) {
          appendValue(field);
        } else {
          throw new IllegalArgumentException("Too many pattern letters: " + cur);
        }
        break;
      case 'd':
      case 'h':
      case 'H':
      case 'k':
      case 'K':
      case 'm':
      case 's':
        if (count == 1) {
          appendValue(field);
        } else if (count == 2) {
          appendValue(field, count);
        } else {
          throw new IllegalArgumentException("Too many pattern letters: " + cur);
        }
        break;
      case 'D':
        if (count == 1) {
          appendValue(field);
        } else if (count <= 3) {
          appendValue(field, count);
        } else {
          throw new IllegalArgumentException("Too many pattern letters: " + cur);
        }
        break;
      default:
        if (count == 1) {
          appendValue(field);
        } else {
          appendValue(field, count);
        }
        break;
    }
  }

  /**
   * Map of letters to fields.
   */
  private static final Map<Character, TemporalField> FIELD_MAP = new HashMap<>();

  static {
    // SDF = SimpleDateFormat
    FIELD_MAP.put('G',
        ChronoField.ERA);                       // SDF, LDML (different to both for 1/2 chars)
    FIELD_MAP.put('y', ChronoField.YEAR_OF_ERA);               // SDF, LDML
    FIELD_MAP.put('u', ChronoField.YEAR);                      // LDML (different in SDF)
    FIELD_MAP.put('Q', IsoFields.QUARTER_OF_YEAR);             // LDML (removed quarter from 310)
    FIELD_MAP.put('q', IsoFields.QUARTER_OF_YEAR);             // LDML (stand-alone)
    FIELD_MAP.put('M', ChronoField.MONTH_OF_YEAR);             // SDF, LDML
    FIELD_MAP.put('L', ChronoField.MONTH_OF_YEAR);             // SDF, LDML (stand-alone)
    FIELD_MAP.put('D', ChronoField.DAY_OF_YEAR);               // SDF, LDML
    FIELD_MAP.put('d', ChronoField.DAY_OF_MONTH);              // SDF, LDML
    FIELD_MAP.put('F', ChronoField.ALIGNED_DAY_OF_WEEK_IN_MONTH);  // SDF, LDML
    FIELD_MAP.put('E',
        ChronoField.DAY_OF_WEEK);               // SDF, LDML (different to both for 1/2 chars)
    FIELD_MAP.put('c', ChronoField.DAY_OF_WEEK);               // LDML (stand-alone)
    FIELD_MAP.put('e', ChronoField.DAY_OF_WEEK);               // LDML (needs localized week number)
    FIELD_MAP.put('a', ChronoField.AMPM_OF_DAY);               // SDF, LDML
    FIELD_MAP.put('H', ChronoField.HOUR_OF_DAY);               // SDF, LDML
    FIELD_MAP.put('k', ChronoField.CLOCK_HOUR_OF_DAY);         // SDF, LDML
    FIELD_MAP.put('K', ChronoField.HOUR_OF_AMPM);              // SDF, LDML
    FIELD_MAP.put('h', ChronoField.CLOCK_HOUR_OF_AMPM);        // SDF, LDML
    FIELD_MAP.put('m', ChronoField.MINUTE_OF_HOUR);            // SDF, LDML
    FIELD_MAP.put('s', ChronoField.SECOND_OF_MINUTE);          // SDF, LDML
    FIELD_MAP
        .put('S', ChronoField.NANO_OF_SECOND);            // LDML (SDF uses milli-of-second number)
    FIELD_MAP.put('A', ChronoField.MILLI_OF_DAY);              // LDML
    FIELD_MAP.put('n', ChronoField.NANO_OF_SECOND);            // 310 (proposed for LDML)
    FIELD_MAP.put('N', ChronoField.NANO_OF_DAY);               // 310 (proposed for LDML)
    // 310 - z - time-zone names, matches LDML and SimpleDateFormat 1 to 4
    // 310 - Z - matches SimpleDateFormat and LDML
    // 310 - V - time-zone id, matches LDML
    // 310 - p - prefix for padding
    // 310 - X - matches LDML, almost matches SDF for 1, exact match 2&3, extended 4&5
    // 310 - x - matches LDML
    // 310 - w, W, and Y are localized forms matching LDML
    // LDML - U - cycle year name, not supported by 310 yet
    // LDML - l - deprecated
    // LDML - j - not relevant
    // LDML - g - modified-julian-day
    // LDML - v,V - extended time-zone names
  }

  //-----------------------------------------------------------------------

  /**
   * Causes the next added printer/parser to pad to a fixed width using a space.
   * <p>
   * This padding will pad to a fixed width using spaces.
   * <p>
   * During formatting, the decorated element will be output and then padded
   * to the specified width. An exception will be thrown during formatting if
   * the pad width is exceeded.
   * <p>
   * During parsing, the padding and decorated element are parsed.
   * If parsing is lenient, then the pad width is treated as a maximum.
   * The padding is parsed greedily. Thus, if the decorated element starts with
   * the pad character, it will not be parsed.
   *
   * @param padWidth the pad width, 1 or greater
   * @return this, for chaining, not null
   * @throws IllegalArgumentException if pad width is too small
   */
  public DateTimeFormatterBuilder padNext(int padWidth) {
    return padNext(padWidth, ' ');
  }

  /**
   * Causes the next added printer/parser to pad to a fixed width.
   * <p>
   * This padding is intended for padding other than zero-padding.
   * Zero-padding should be achieved using the appendValue methods.
   * <p>
   * During formatting, the decorated element will be output and then padded
   * to the specified width. An exception will be thrown during formatting if
   * the pad width is exceeded.
   * <p>
   * During parsing, the padding and decorated element are parsed.
   * If parsing is lenient, then the pad width is treated as a maximum.
   * If parsing is case insensitive, then the pad character is matched ignoring case.
   * The padding is parsed greedily. Thus, if the decorated element starts with
   * the pad character, it will not be parsed.
   *
   * @param padWidth the pad width, 1 or greater
   * @param padChar the pad character
   * @return this, for chaining, not null
   * @throws IllegalArgumentException if pad width is too small
   */
  public DateTimeFormatterBuilder padNext(int padWidth, char padChar) {
    if (padWidth < 1) {
      throw new IllegalArgumentException("The pad width must be at least one but was " + padWidth);
    }
    active.padNextWidth = padWidth;
    active.padNextChar = padChar;
    active.valueParserIndex = -1;
    return this;
  }

  //-----------------------------------------------------------------------

  /**
   * Mark the start of an optional section. <p> The output of formatting can include optional
   * sections, which may be nested. An optional section is started by calling this method and ended
   * by calling {@link #optionalEnd()} or by ending the build process. <p> All elements in the
   * optional section are treated as optional. During formatting, the section is only output if data
   * is available in the {@code TemporalAccessor} for all the elements in the section. During
   * parsing, the whole section may be missing from the parsed string. <p> For example, consider a
   * builder setup as {@code builder.appendValue(HOUR_OF_DAY,2).optionalStart().appendValue(MINUTE_OF_HOUR,2)}.
   * The optional section ends automatically at the end of the builder. During formatting, the
   * minute will only be output if its value can be obtained from the date-time. During parsing, the
   * input will be successfully parsed whether the minute is present or not.
   *
   * @return this, for chaining, not null
   */
  public DateTimeFormatterBuilder optionalStart() {
    active.valueParserIndex = -1;
    active = new DateTimeFormatterBuilder(active, true);
    return this;
  }

  /**
   * Ends an optional section. <p> The output of formatting can include optional sections, which may
   * be nested. An optional section is started by calling {@link #optionalStart()} and ended using
   * this method (or at the end of the builder). <p> Calling this method without having previously
   * called {@code optionalStart} will throw an exception. Calling this method immediately after
   * calling {@code optionalStart} has no effect on the formatter other than ending the (empty)
   * optional section. <p> All elements in the optional section are treated as optional. During
   * formatting, the section is only output if data is available in the {@code TemporalAccessor} for
   * all the elements in the section. During parsing, the whole section may be missing from the
   * parsed string. <p> For example, consider a builder setup as {@code
   * builder.appendValue(HOUR_OF_DAY,2).optionalStart().appendValue(MINUTE_OF_HOUR,2).optionalEnd()}.
   * During formatting, the minute will only be output if its value can be obtained from the
   * date-time. During parsing, the input will be successfully parsed whether the minute is present
   * or not.
   *
   * @return this, for chaining, not null
   * @throws IllegalStateException if there was no previous call to {@code optionalStart}
   */
  public DateTimeFormatterBuilder optionalEnd() {
    if (active.parent == null) {
      throw new IllegalStateException(
          "Cannot call optionalEnd() as there was no previous call to optionalStart()");
    }
    if (active.printerParsers.size() > 0) {
      CompositePrinterParser cpp = new CompositePrinterParser(active.printerParsers,
          active.optional);
      active = active.parent;
      appendInternal(cpp);
    } else {
      active = active.parent;
    }
    return this;
  }

  //-----------------------------------------------------------------------

  /**
   * Appends a printer and/or parser to the internal list handling padding.
   *
   * @param pp the printer-parser to add, not null
   * @return the index into the active parsers list
   */
  private int appendInternal(DateTimePrinterParser pp) {
    Objects.requireNonNull(pp, "pp");
    if (active.padNextWidth > 0) {
      if (pp != null) {
        pp = new PadPrinterParserDecorator(pp, active.padNextWidth, active.padNextChar);
      }
      active.padNextWidth = 0;
      active.padNextChar = 0;
    }
    active.printerParsers.add(pp);
    active.valueParserIndex = -1;
    return active.printerParsers.size() - 1;
  }

  //-----------------------------------------------------------------------

  /**
   * Completes this builder by creating the {@code DateTimeFormatter} using the default locale. <p>
   * This will create a formatter with the {@linkplain Locale#getDefault(Locale.Category) default
   * FORMAT locale}. Numbers will be printed and parsed using the standard DecimalStyle. The
   * resolver style will be {@link ResolverStyle#SMART SMART}. <p> Calling this method will end any
   * open optional sections by repeatedly calling {@link #optionalEnd()} before creating the
   * formatter. <p> This builder can still be used after creating the formatter if desired, although
   * the state may have been changed by calls to {@code optionalEnd}.
   *
   * @return the created formatter, not null
   */
  public DateTimeFormatter toFormatter() {
    return toFormatter(Locale.getDefault(Locale.Category.FORMAT));
  }

  /**
   * Completes this builder by creating the {@code DateTimeFormatter}
   * using the specified locale.
   * <p>
   * This will create a formatter with the specified locale.
   * Numbers will be printed and parsed using the standard DecimalStyle.
   * The resolver style will be {@link ResolverStyle#SMART SMART}.
   * <p>
   * Calling this method will end any open optional sections by repeatedly
   * calling {@link #optionalEnd()} before creating the formatter.
   * <p>
   * This builder can still be used after creating the formatter if desired,
   * although the state may have been changed by calls to {@code optionalEnd}.
   *
   * @param locale the locale to use for formatting, not null
   * @return the created formatter, not null
   */
  public DateTimeFormatter toFormatter(Locale locale) {
    return toFormatter(locale, ResolverStyle.SMART, null);
  }

  /**
   * Completes this builder by creating the formatter.
   * This uses the default locale.
   *
   * @param resolverStyle the resolver style to use, not null
   * @return the created formatter, not null
   */
  DateTimeFormatter toFormatter(ResolverStyle resolverStyle, Chronology chrono) {
    return toFormatter(Locale.getDefault(Locale.Category.FORMAT), resolverStyle, chrono);
  }

  /**
   * Completes this builder by creating the formatter.
   *
   * @param locale the locale to use for formatting, not null
   * @param chrono the chronology to use, may be null
   * @return the created formatter, not null
   */
  private DateTimeFormatter toFormatter(Locale locale, ResolverStyle resolverStyle,
      Chronology chrono) {
    Objects.requireNonNull(locale, "locale");
    while (active.parent != null) {
      optionalEnd();
    }
    CompositePrinterParser pp = new CompositePrinterParser(printerParsers, false);
    return new DateTimeFormatter(pp, locale, DecimalStyle.STANDARD,
        resolverStyle, null, chrono, null);
  }

  //-----------------------------------------------------------------------

  /**
   * Strategy for formatting/parsing date-time information.
   * <p>
   * The printer may format any part, or the whole, of the input date-time object.
   * Typically, a complete format is constructed from a number of smaller
   * units, each outputting a single field.
   * <p>
   * The parser may parse any piece of text from the input, storing the result
   * in the context. Typically, each individual parser will just parse one
   * field, such as the day-of-month, storing the value in the context.
   * Once the parse is complete, the caller will then resolve the parsed values
   * to create the desired object, such as a {@code LocalDate}.
   * <p>
   * The parse position will be updated during the parse. Parsing will start at
   * the specified index and the return value specifies the new parse position
   * for the next parser. If an error occurs, the returned index will be negative
   * and will have the error position encoded using the complement operator.
   *
   * @implSpec This interface must be implemented with care to ensure other classes operate
   * correctly. All implementations that can be instantiated must be final, immutable and
   * thread-safe. <p> The context is not a thread-safe object and a new instance will be created for
   * each format that occurs. The context must not be stored in an instance variable or shared with
   * any other threads.
   */
  interface DateTimePrinterParser {

    /**
     * Prints the date-time object to the buffer.
     * <p>
     * The context holds information to use during the format.
     * It also contains the date-time information to be printed.
     * <p>
     * The buffer must not be mutated beyond the content controlled by the implementation.
     *
     * @param context the context to format using, not null
     * @param buf the buffer to append to, not null
     * @return false if unable to query the value from the date-time, true otherwise
     * @throws DateTimeException if the date-time cannot be printed successfully
     */
    boolean format(DateTimePrintContext context, StringBuilder buf);

    /**
     * Parses text into date-time information.
     * <p>
     * The context holds information to use during the parse.
     * It is also used to store the parsed date-time information.
     *
     * @param context the context to use and parse into, not null
     * @param text the input text to parse, not null
     * @param position the position to start parsing at, from 0 to the text length
     * @return the new parse position, where negative means an error with the error position encoded
     * using the complement ~ operator
     * @throws NullPointerException if the context or text is null
     * @throws IndexOutOfBoundsException if the position is invalid
     */
    int parse(DateTimeParseContext context, CharSequence text, int position);
  }

  //-----------------------------------------------------------------------

  /**
   * Composite printer and parser.
   */
  static final class CompositePrinterParser implements DateTimePrinterParser {

    private final DateTimePrinterParser[] printerParsers;
    private final boolean optional;

    CompositePrinterParser(List<DateTimePrinterParser> printerParsers, boolean optional) {
      this(printerParsers.toArray(new DateTimePrinterParser[printerParsers.size()]), optional);
    }

    CompositePrinterParser(DateTimePrinterParser[] printerParsers, boolean optional) {
      this.printerParsers = printerParsers;
      this.optional = optional;
    }

    /**
     * Returns a copy of this printer-parser with the optional flag changed.
     *
     * @param optional the optional flag to set in the copy
     * @return the new printer-parser, not null
     */
    public CompositePrinterParser withOptional(boolean optional) {
      if (optional == this.optional) {
        return this;
      }
      return new CompositePrinterParser(printerParsers, optional);
    }

    @Override
    public boolean format(DateTimePrintContext context, StringBuilder buf) {
      int length = buf.length();
      if (optional) {
        context.startOptional();
      }
      try {
        for (DateTimePrinterParser pp : printerParsers) {
          if (pp.format(context, buf) == false) {
            buf.setLength(length);  // reset buffer
            return true;
          }
        }
      } finally {
        if (optional) {
          context.endOptional();
        }
      }
      return true;
    }

    @Override
    public int parse(DateTimeParseContext context, CharSequence text, int position) {
      if (optional) {
        context.startOptional();
        int pos = position;
        for (DateTimePrinterParser pp : printerParsers) {
          pos = pp.parse(context, text, pos);
          if (pos < 0) {
            context.endOptional(false);
            return position;  // return original position
          }
        }
        context.endOptional(true);
        return pos;
      } else {
        for (DateTimePrinterParser pp : printerParsers) {
          position = pp.parse(context, text, position);
          if (position < 0) {
            break;
          }
        }
        return position;
      }
    }

    @Override
    public String toString() {
      StringBuilder buf = new StringBuilder();
      if (printerParsers != null) {
        buf.append(optional ? "[" : "(");
        for (DateTimePrinterParser pp : printerParsers) {
          buf.append(pp);
        }
        buf.append(optional ? "]" : ")");
      }
      return buf.toString();
    }
  }

  //-----------------------------------------------------------------------

  /**
   * Pads the output to a fixed width.
   */
  static final class PadPrinterParserDecorator implements DateTimePrinterParser {

    private final DateTimePrinterParser printerParser;
    private final int padWidth;
    private final char padChar;

    /**
     * Constructor.
     *
     * @param printerParser the printer, not null
     * @param padWidth the width to pad to, 1 or greater
     * @param padChar the pad character
     */
    PadPrinterParserDecorator(DateTimePrinterParser printerParser, int padWidth, char padChar) {
      // input checked by DateTimeFormatterBuilder
      this.printerParser = printerParser;
      this.padWidth = padWidth;
      this.padChar = padChar;
    }

    @Override
    public boolean format(DateTimePrintContext context, StringBuilder buf) {
      int preLen = buf.length();
      if (printerParser.format(context, buf) == false) {
        return false;
      }
      int len = buf.length() - preLen;
      if (len > padWidth) {
        throw new DateTimeException(
            "Cannot print as output of " + len + " characters exceeds pad width of " + padWidth);
      }
      for (int i = 0; i < padWidth - len; i++) {
        buf.insert(preLen, padChar);
      }
      return true;
    }

    @Override
    public int parse(DateTimeParseContext context, CharSequence text, int position) {
      // cache context before changed by decorated parser
      final boolean strict = context.isStrict();
      // parse
      if (position > text.length()) {
        throw new IndexOutOfBoundsException();
      }
      if (position == text.length()) {
        return ~position;  // no more characters in the string
      }
      int endPos = position + padWidth;
      if (endPos > text.length()) {
        if (strict) {
          return ~position;  // not enough characters in the string to meet the parse width
        }
        endPos = text.length();
      }
      int pos = position;
      while (pos < endPos && context.charEquals(text.charAt(pos), padChar)) {
        pos++;
      }
      text = text.subSequence(0, endPos);
      int resultPos = printerParser.parse(context, text, pos);
      if (resultPos != endPos && strict) {
        return ~(position + pos);  // parse of decorated field didn't parse to the end
      }
      return resultPos;
    }

    @Override
    public String toString() {
      return "Pad(" + printerParser + "," + padWidth + (padChar == ' ' ? ")"
          : ",'" + padChar + "')");
    }
  }

  //-----------------------------------------------------------------------

  /**
   * Enumeration to apply simple parse settings.
   */
  static enum SettingsParser implements DateTimePrinterParser {
    SENSITIVE,
    INSENSITIVE,
    STRICT,
    LENIENT;

    @Override
    public boolean format(DateTimePrintContext context, StringBuilder buf) {
      return true;  // nothing to do here
    }

    @Override
    public int parse(DateTimeParseContext context, CharSequence text, int position) {
      // using ordinals to avoid javac synthetic inner class
      switch (ordinal()) {
        case 0:
          context.setCaseSensitive(true);
          break;
        case 1:
          context.setCaseSensitive(false);
          break;
        case 2:
          context.setStrict(true);
          break;
        case 3:
          context.setStrict(false);
          break;
      }
      return position;
    }

    @Override
    public String toString() {
      // using ordinals to avoid javac synthetic inner class
      switch (ordinal()) {
        case 0:
          return "ParseCaseSensitive(true)";
        case 1:
          return "ParseCaseSensitive(false)";
        case 2:
          return "ParseStrict(true)";
        case 3:
          return "ParseStrict(false)";
      }
      throw new IllegalStateException("Unreachable");
    }
  }

  //-----------------------------------------------------------------------

  /**
   * Defaults a value into the parse if not currently present.
   */
  static class DefaultValueParser implements DateTimePrinterParser {

    private final TemporalField field;
    private final long value;

    DefaultValueParser(TemporalField field, long value) {
      this.field = field;
      this.value = value;
    }

    public boolean format(DateTimePrintContext context, StringBuilder buf) {
      return true;
    }

    public int parse(DateTimeParseContext context, CharSequence text, int position) {
      if (context.getParsed(field) == null) {
        context.setParsedField(field, value, position, position);
      }
      return position;
    }
  }

  //-----------------------------------------------------------------------

  /**
   * Prints or parses a character literal.
   */
  static final class CharLiteralPrinterParser implements DateTimePrinterParser {

    private final char literal;

    CharLiteralPrinterParser(char literal) {
      this.literal = literal;
    }

    @Override
    public boolean format(DateTimePrintContext context, StringBuilder buf) {
      buf.append(literal);
      return true;
    }

    @Override
    public int parse(DateTimeParseContext context, CharSequence text, int position) {
      int length = text.length();
      if (position == length) {
        return ~position;
      }
      char ch = text.charAt(position);
      if (ch != literal) {
        if (context.isCaseSensitive() ||
            (Character.toUpperCase(ch) != Character.toUpperCase(literal) &&
                Character.toLowerCase(ch) != Character.toLowerCase(literal))) {
          return ~position;
        }
      }
      return position + 1;
    }

    @Override
    public String toString() {
      if (literal == '\'') {
        return "''";
      }
      return "'" + literal + "'";
    }
  }

  //-----------------------------------------------------------------------

  /**
   * Prints or parses a string literal.
   */
  static final class StringLiteralPrinterParser implements DateTimePrinterParser {

    private final String literal;

    StringLiteralPrinterParser(String literal) {
      this.literal = literal;  // validated by caller
    }

    @Override
    public boolean format(DateTimePrintContext context, StringBuilder buf) {
      buf.append(literal);
      return true;
    }

    @Override
    public int parse(DateTimeParseContext context, CharSequence text, int position) {
      int length = text.length();
      if (position > length || position < 0) {
        throw new IndexOutOfBoundsException();
      }
      if (context.subSequenceEquals(text, position, literal, 0, literal.length()) == false) {
        return ~position;
      }
      return position + literal.length();
    }

    @Override
    public String toString() {
      String converted = literal.replace("'", "''");
      return "'" + converted + "'";
    }
  }

  //-----------------------------------------------------------------------

  /**
   * Prints and parses a numeric date-time field with optional padding.
   */
  static class NumberPrinterParser implements DateTimePrinterParser {

    /**
     * Array of 10 to the power of n.
     */
    static final long[] EXCEED_POINTS = new long[]{
        0L,
        10L,
        100L,
        1000L,
        10000L,
        100000L,
        1000000L,
        10000000L,
        100000000L,
        1000000000L,
        10000000000L,
    };

    final TemporalField field;
    final int minWidth;
    final int maxWidth;
    private final SignStyle signStyle;
    final int subsequentWidth;

    /**
     * Constructor.
     *
     * @param field the field to format, not null
     * @param minWidth the minimum field width, from 1 to 19
     * @param maxWidth the maximum field width, from minWidth to 19
     * @param signStyle the positive/negative sign style, not null
     */
    NumberPrinterParser(TemporalField field, int minWidth, int maxWidth, SignStyle signStyle) {
      // validated by caller
      this.field = field;
      this.minWidth = minWidth;
      this.maxWidth = maxWidth;
      this.signStyle = signStyle;
      this.subsequentWidth = 0;
    }

    /**
     * Constructor.
     *
     * @param field the field to format, not null
     * @param minWidth the minimum field width, from 1 to 19
     * @param maxWidth the maximum field width, from minWidth to 19
     * @param signStyle the positive/negative sign style, not null
     * @param subsequentWidth the width of subsequent non-negative numbers, 0 or greater, -1 if
     * fixed width due to active adjacent parsing
     */
    protected NumberPrinterParser(TemporalField field, int minWidth, int maxWidth,
        SignStyle signStyle, int subsequentWidth) {
      // validated by caller
      this.field = field;
      this.minWidth = minWidth;
      this.maxWidth = maxWidth;
      this.signStyle = signStyle;
      this.subsequentWidth = subsequentWidth;
    }

    /**
     * Returns a new instance with fixed width flag set.
     *
     * @return a new updated printer-parser, not null
     */
    NumberPrinterParser withFixedWidth() {
      if (subsequentWidth == -1) {
        return this;
      }
      return new NumberPrinterParser(field, minWidth, maxWidth, signStyle, -1);
    }

    /**
     * Returns a new instance with an updated subsequent width.
     *
     * @param subsequentWidth the width of subsequent non-negative numbers, 0 or greater
     * @return a new updated printer-parser, not null
     */
    NumberPrinterParser withSubsequentWidth(int subsequentWidth) {
      return new NumberPrinterParser(field, minWidth, maxWidth, signStyle,
          this.subsequentWidth + subsequentWidth);
    }

    @Override
    public boolean format(DateTimePrintContext context, StringBuilder buf) {
      Long valueLong = context.getValue(field);
      if (valueLong == null) {
        return false;
      }
      long value = getValue(context, valueLong);
      DecimalStyle decimalStyle = context.getDecimalStyle();
      String str = (value == Long.MIN_VALUE ? "9223372036854775808"
          : Long.toString(Math.abs(value)));
      if (str.length() > maxWidth) {
        throw new DateTimeException("Field " + field +
            " cannot be printed as the value " + value +
            " exceeds the maximum print width of " + maxWidth);
      }
      str = decimalStyle.convertNumberToI18N(str);

      if (value >= 0) {
        switch (signStyle) {
          case EXCEEDS_PAD:
            if (minWidth < 19 && value >= EXCEED_POINTS[minWidth]) {
              buf.append(decimalStyle.getPositiveSign());
            }
            break;
          case ALWAYS:
            buf.append(decimalStyle.getPositiveSign());
            break;
        }
      } else {
        switch (signStyle) {
          case NORMAL:
          case EXCEEDS_PAD:
          case ALWAYS:
            buf.append(decimalStyle.getNegativeSign());
            break;
          case NOT_NEGATIVE:
            throw new DateTimeException("Field " + field +
                " cannot be printed as the value " + value +
                " cannot be negative according to the SignStyle");
        }
      }
      for (int i = 0; i < minWidth - str.length(); i++) {
        buf.append(decimalStyle.getZeroDigit());
      }
      buf.append(str);
      return true;
    }

    /**
     * Gets the value to output.
     *
     * @param context the context
     * @param value the value of the field, not null
     * @return the value
     */
    long getValue(DateTimePrintContext context, long value) {
      return value;
    }

    /**
     * For NumberPrinterParser, the width is fixed depending on the
     * minWidth, maxWidth, signStyle and whether subsequent fields are fixed.
     *
     * @param context the context
     * @return true if the field is fixed width
     * @see DateTimeFormatterBuilder#appendValue(java.time.temporal.TemporalField, int)
     */
    boolean isFixedWidth(DateTimeParseContext context) {
      return subsequentWidth == -1 ||
          (subsequentWidth > 0 && minWidth == maxWidth && signStyle == SignStyle.NOT_NEGATIVE);
    }

    @Override
    public int parse(DateTimeParseContext context, CharSequence text, int position) {
      int length = text.length();
      if (position == length) {
        return ~position;
      }
      char sign = text.charAt(position);  // IOOBE if invalid position
      boolean negative = false;
      boolean positive = false;
      if (sign == context.getDecimalStyle().getPositiveSign()) {
        if (signStyle.parse(true, context.isStrict(), minWidth == maxWidth) == false) {
          return ~position;
        }
        positive = true;
        position++;
      } else if (sign == context.getDecimalStyle().getNegativeSign()) {
        if (signStyle.parse(false, context.isStrict(), minWidth == maxWidth) == false) {
          return ~position;
        }
        negative = true;
        position++;
      } else {
        if (signStyle == SignStyle.ALWAYS && context.isStrict()) {
          return ~position;
        }
      }
      int effMinWidth = (context.isStrict() || isFixedWidth(context) ? minWidth : 1);
      int minEndPos = position + effMinWidth;
      if (minEndPos > length) {
        return ~position;
      }
      int effMaxWidth = (context.isStrict() || isFixedWidth(context) ? maxWidth : 9) + Math
          .max(subsequentWidth, 0);
      long total = 0;
      BigInteger totalBig = null;
      int pos = position;
      for (int pass = 0; pass < 2; pass++) {
        int maxEndPos = Math.min(pos + effMaxWidth, length);
        while (pos < maxEndPos) {
          char ch = text.charAt(pos++);
          int digit = context.getDecimalStyle().convertToDigit(ch);
          if (digit < 0) {
            pos--;
            if (pos < minEndPos) {
              return ~position;  // need at least min width digits
            }
            break;
          }
          if ((pos - position) > 18) {
            if (totalBig == null) {
              totalBig = BigInteger.valueOf(total);
            }
            totalBig = totalBig.multiply(BigInteger.TEN).add(BigInteger.valueOf(digit));
          } else {
            total = total * 10 + digit;
          }
        }
        if (subsequentWidth > 0 && pass == 0) {
          // re-parse now we know the correct width
          int parseLen = pos - position;
          effMaxWidth = Math.max(effMinWidth, parseLen - subsequentWidth);
          pos = position;
          total = 0;
          totalBig = null;
        } else {
          break;
        }
      }
      if (negative) {
        if (totalBig != null) {
          if (totalBig.equals(BigInteger.ZERO) && context.isStrict()) {
            return ~(position - 1);  // minus zero not allowed
          }
          totalBig = totalBig.negate();
        } else {
          if (total == 0 && context.isStrict()) {
            return ~(position - 1);  // minus zero not allowed
          }
          total = -total;
        }
      } else if (signStyle == SignStyle.EXCEEDS_PAD && context.isStrict()) {
        int parseLen = pos - position;
        if (positive) {
          if (parseLen <= minWidth) {
            return ~(position - 1);  // '+' only parsed if minWidth exceeded
          }
        } else {
          if (parseLen > minWidth) {
            return ~position;  // '+' must be parsed if minWidth exceeded
          }
        }
      }
      if (totalBig != null) {
        if (totalBig.bitLength() > 63) {
          // overflow, parse 1 less digit
          totalBig = totalBig.divide(BigInteger.TEN);
          pos--;
        }
        return setValue(context, totalBig.longValue(), position, pos);
      }
      return setValue(context, total, position, pos);
    }

    /**
     * Stores the value.
     *
     * @param context the context to store into, not null
     * @param value the value
     * @param errorPos the position of the field being parsed
     * @param successPos the position after the field being parsed
     * @return the new position
     */
    int setValue(DateTimeParseContext context, long value, int errorPos, int successPos) {
      return context.setParsedField(field, value, errorPos, successPos);
    }

    @Override
    public String toString() {
      if (minWidth == 1 && maxWidth == 19 && signStyle == SignStyle.NORMAL) {
        return "Value(" + field + ")";
      }
      if (minWidth == maxWidth && signStyle == SignStyle.NOT_NEGATIVE) {
        return "Value(" + field + "," + minWidth + ")";
      }
      return "Value(" + field + "," + minWidth + "," + maxWidth + "," + signStyle + ")";
    }
  }

  //-----------------------------------------------------------------------

  /**
   * Prints and parses a reduced numeric date-time field.
   */
  static final class ReducedPrinterParser extends NumberPrinterParser {

    /**
     * The base date for reduced value parsing.
     */
    static final LocalDate BASE_DATE = LocalDate.of(2000, 1, 1);

    private final int baseValue;
    private final ChronoLocalDate baseDate;

    /**
     * Constructor.
     *
     * @param field the field to format, validated not null
     * @param minWidth the minimum field width, from 1 to 10
     * @param maxWidth the maximum field width, from 1 to 10
     * @param baseValue the base value
     * @param baseDate the base date
     */
    ReducedPrinterParser(TemporalField field, int minWidth, int maxWidth,
        int baseValue, ChronoLocalDate baseDate) {
      this(field, minWidth, maxWidth, baseValue, baseDate, 0);
      if (minWidth < 1 || minWidth > 10) {
        throw new IllegalArgumentException(
            "The minWidth must be from 1 to 10 inclusive but was " + minWidth);
      }
      if (maxWidth < 1 || maxWidth > 10) {
        throw new IllegalArgumentException(
            "The maxWidth must be from 1 to 10 inclusive but was " + minWidth);
      }
      if (maxWidth < minWidth) {
        throw new IllegalArgumentException(
            "Maximum width must exceed or equal the minimum width but " +
                maxWidth + " < " + minWidth);
      }
      if (baseDate == null) {
        if (field.range().isValidValue(baseValue) == false) {
          throw new IllegalArgumentException(
              "The base value must be within the range of the field");
        }
        if ((((long) baseValue) + EXCEED_POINTS[maxWidth]) > Integer.MAX_VALUE) {
          throw new DateTimeException(
              "Unable to add printer-parser as the range exceeds the capacity of an int");
        }
      }
    }

    /**
     * Constructor.
     * The arguments have already been checked.
     *
     * @param field the field to format, validated not null
     * @param minWidth the minimum field width, from 1 to 10
     * @param maxWidth the maximum field width, from 1 to 10
     * @param baseValue the base value
     * @param baseDate the base date
     * @param subsequentWidth the subsequentWidth for this instance
     */
    private ReducedPrinterParser(TemporalField field, int minWidth, int maxWidth,
        int baseValue, ChronoLocalDate baseDate, int subsequentWidth) {
      super(field, minWidth, maxWidth, SignStyle.NOT_NEGATIVE, subsequentWidth);
      this.baseValue = baseValue;
      this.baseDate = baseDate;
    }

    @Override
    long getValue(DateTimePrintContext context, long value) {
      long absValue = Math.abs(value);
      int baseValue = this.baseValue;
      if (baseDate != null) {
        Chronology chrono = Chronology.from(context.getTemporal());
        baseValue = chrono.date(baseDate).get(field);
      }
      if (value >= baseValue && value < baseValue + EXCEED_POINTS[minWidth]) {
        // Use the reduced value if it fits in minWidth
        return absValue % EXCEED_POINTS[minWidth];
      }
      // Otherwise truncate to fit in maxWidth
      return absValue % EXCEED_POINTS[maxWidth];
    }

    @Override
    int setValue(DateTimeParseContext context, long value, int errorPos, int successPos) {
      int baseValue = this.baseValue;
      if (baseDate != null) {
        Chronology chrono = context.getEffectiveChronology();
        baseValue = chrono.date(baseDate).get(field);

        // In case the Chronology is changed later, add a callback when/if it changes
        final long initialValue = value;
        context.addChronoChangedListener(
            (_unused) -> {
                            /* Repeat the set of the field using the current Chronology
                             * The success/error position is ignored because the value is
                             * intentionally being overwritten.
                             */
              setValue(context, initialValue, errorPos, successPos);
            });
      }
      int parseLen = successPos - errorPos;
      if (parseLen == minWidth && value >= 0) {
        long range = EXCEED_POINTS[minWidth];
        long lastPart = baseValue % range;
        long basePart = baseValue - lastPart;
        if (baseValue > 0) {
          value = basePart + value;
        } else {
          value = basePart - value;
        }
        if (value < baseValue) {
          value += range;
        }
      }
      return context.setParsedField(field, value, errorPos, successPos);
    }

    /**
     * Returns a new instance with fixed width flag set.
     *
     * @return a new updated printer-parser, not null
     */
    @Override
    ReducedPrinterParser withFixedWidth() {
      if (subsequentWidth == -1) {
        return this;
      }
      return new ReducedPrinterParser(field, minWidth, maxWidth, baseValue, baseDate, -1);
    }

    /**
     * Returns a new instance with an updated subsequent width.
     *
     * @param subsequentWidth the width of subsequent non-negative numbers, 0 or greater
     * @return a new updated printer-parser, not null
     */
    @Override
    ReducedPrinterParser withSubsequentWidth(int subsequentWidth) {
      return new ReducedPrinterParser(field, minWidth, maxWidth, baseValue, baseDate,
          this.subsequentWidth + subsequentWidth);
    }

    /**
     * For a ReducedPrinterParser, fixed width is false if the mode is strict,
     * otherwise it is set as for NumberPrinterParser.
     *
     * @param context the context
     * @return if the field is fixed width
     * @see DateTimeFormatterBuilder#appendValueReduced(java.time.temporal.TemporalField, int, int,
     * int)
     */
    @Override
    boolean isFixedWidth(DateTimeParseContext context) {
      if (context.isStrict() == false) {
        return false;
      }
      return super.isFixedWidth(context);
    }

    @Override
    public String toString() {
      return "ReducedValue(" + field + "," + minWidth + "," + maxWidth + "," + (baseDate != null
          ? baseDate : baseValue) + ")";
    }
  }

  //-----------------------------------------------------------------------

  /**
   * Prints and parses a numeric date-time field with optional padding.
   */
  static final class FractionPrinterParser implements DateTimePrinterParser {

    private final TemporalField field;
    private final int minWidth;
    private final int maxWidth;
    private final boolean decimalPoint;

    /**
     * Constructor.
     *
     * @param field the field to output, not null
     * @param minWidth the minimum width to output, from 0 to 9
     * @param maxWidth the maximum width to output, from 0 to 9
     * @param decimalPoint whether to output the localized decimal point symbol
     */
    FractionPrinterParser(TemporalField field, int minWidth, int maxWidth, boolean decimalPoint) {
      Objects.requireNonNull(field, "field");
      if (field.range().isFixed() == false) {
        throw new IllegalArgumentException("Field must have a fixed set of values: " + field);
      }
      if (minWidth < 0 || minWidth > 9) {
        throw new IllegalArgumentException(
            "Minimum width must be from 0 to 9 inclusive but was " + minWidth);
      }
      if (maxWidth < 1 || maxWidth > 9) {
        throw new IllegalArgumentException(
            "Maximum width must be from 1 to 9 inclusive but was " + maxWidth);
      }
      if (maxWidth < minWidth) {
        throw new IllegalArgumentException(
            "Maximum width must exceed or equal the minimum width but " +
                maxWidth + " < " + minWidth);
      }
      this.field = field;
      this.minWidth = minWidth;
      this.maxWidth = maxWidth;
      this.decimalPoint = decimalPoint;
    }

    @Override
    public boolean format(DateTimePrintContext context, StringBuilder buf) {
      Long value = context.getValue(field);
      if (value == null) {
        return false;
      }
      DecimalStyle decimalStyle = context.getDecimalStyle();
      BigDecimal fraction = convertToFraction(value);
      if (fraction.scale() == 0) {  // scale is zero if value is zero
        if (minWidth > 0) {
          if (decimalPoint) {
            buf.append(decimalStyle.getDecimalSeparator());
          }
          for (int i = 0; i < minWidth; i++) {
            buf.append(decimalStyle.getZeroDigit());
          }
        }
      } else {
        int outputScale = Math.min(Math.max(fraction.scale(), minWidth), maxWidth);
        fraction = fraction.setScale(outputScale, RoundingMode.FLOOR);
        String str = fraction.toPlainString().substring(2);
        str = decimalStyle.convertNumberToI18N(str);
        if (decimalPoint) {
          buf.append(decimalStyle.getDecimalSeparator());
        }
        buf.append(str);
      }
      return true;
    }

    @Override
    public int parse(DateTimeParseContext context, CharSequence text, int position) {
      int effectiveMin = (context.isStrict() ? minWidth : 0);
      int effectiveMax = (context.isStrict() ? maxWidth : 9);
      int length = text.length();
      if (position == length) {
        // valid if whole field is optional, invalid if minimum width
        return (effectiveMin > 0 ? ~position : position);
      }
      if (decimalPoint) {
        if (text.charAt(position) != context.getDecimalStyle().getDecimalSeparator()) {
          // valid if whole field is optional, invalid if minimum width
          return (effectiveMin > 0 ? ~position : position);
        }
        position++;
      }
      int minEndPos = position + effectiveMin;
      if (minEndPos > length) {
        return ~position;  // need at least min width digits
      }
      int maxEndPos = Math.min(position + effectiveMax, length);
      int total = 0;  // can use int because we are only parsing up to 9 digits
      int pos = position;
      while (pos < maxEndPos) {
        char ch = text.charAt(pos++);
        int digit = context.getDecimalStyle().convertToDigit(ch);
        if (digit < 0) {
          if (pos < minEndPos) {
            return ~position;  // need at least min width digits
          }
          pos--;
          break;
        }
        total = total * 10 + digit;
      }
      BigDecimal fraction = new BigDecimal(total).movePointLeft(pos - position);
      long value = convertFromFraction(fraction);
      return context.setParsedField(field, value, position, pos);
    }

    /**
     * Converts a value for this field to a fraction between 0 and 1. <p> The fractional value is
     * between 0 (inclusive) and 1 (exclusive). It can only be returned if the {@link
     * java.time.temporal.TemporalField#range() value range} is fixed. The fraction is obtained by
     * calculation from the field range using 9 decimal places and a rounding mode of {@link
     * RoundingMode#FLOOR FLOOR}. The calculation is inaccurate if the values do not run
     * continuously from smallest to largest. <p> For example, the second-of-minute value of 15
     * would be returned as 0.25, assuming the standard definition of 60 seconds in a minute.
     *
     * @param value the value to convert, must be valid for this rule
     * @return the value as a fraction within the range, from 0 to 1, not null
     * @throws DateTimeException if the value cannot be converted to a fraction
     */
    private BigDecimal convertToFraction(long value) {
      ValueRange range = field.range();
      range.checkValidValue(value, field);
      BigDecimal minBD = BigDecimal.valueOf(range.getMinimum());
      BigDecimal rangeBD = BigDecimal.valueOf(range.getMaximum()).subtract(minBD)
          .add(BigDecimal.ONE);
      BigDecimal valueBD = BigDecimal.valueOf(value).subtract(minBD);
      BigDecimal fraction = valueBD.divide(rangeBD, 9, RoundingMode.FLOOR);
      // stripTrailingZeros bug
      return fraction.compareTo(BigDecimal.ZERO) == 0 ? BigDecimal.ZERO
          : fraction.stripTrailingZeros();
    }

    /**
     * Converts a fraction from 0 to 1 for this field to a value. <p> The fractional value must be
     * between 0 (inclusive) and 1 (exclusive). It can only be returned if the {@link
     * java.time.temporal.TemporalField#range() value range} is fixed. The value is obtained by
     * calculation from the field range and a rounding mode of {@link RoundingMode#FLOOR FLOOR}. The
     * calculation is inaccurate if the values do not run continuously from smallest to largest. <p>
     * For example, the fractional second-of-minute of 0.25 would be converted to 15, assuming the
     * standard definition of 60 seconds in a minute.
     *
     * @param fraction the fraction to convert, not null
     * @return the value of the field, valid for this rule
     * @throws DateTimeException if the value cannot be converted
     */
    private long convertFromFraction(BigDecimal fraction) {
      ValueRange range = field.range();
      BigDecimal minBD = BigDecimal.valueOf(range.getMinimum());
      BigDecimal rangeBD = BigDecimal.valueOf(range.getMaximum()).subtract(minBD)
          .add(BigDecimal.ONE);
      BigDecimal valueBD = fraction.multiply(rangeBD).setScale(0, RoundingMode.FLOOR).add(minBD);
      return valueBD.longValueExact();
    }

    @Override
    public String toString() {
      String decimal = (decimalPoint ? ",DecimalPoint" : "");
      return "Fraction(" + field + "," + minWidth + "," + maxWidth + decimal + ")";
    }
  }

  //-----------------------------------------------------------------------

  /**
   * Prints or parses field text.
   */
  static final class TextPrinterParser implements DateTimePrinterParser {

    private final TemporalField field;
    private final TextStyle textStyle;
    private final DateTimeTextProvider provider;
    /**
     * The cached number printer parser.
     * Immutable and volatile, so no synchronization needed.
     */
    private volatile NumberPrinterParser numberPrinterParser;

    /**
     * Constructor.
     *
     * @param field the field to output, not null
     * @param textStyle the text style, not null
     * @param provider the text provider, not null
     */
    TextPrinterParser(TemporalField field, TextStyle textStyle, DateTimeTextProvider provider) {
      // validated by caller
      this.field = field;
      this.textStyle = textStyle;
      this.provider = provider;
    }

    @Override
    public boolean format(DateTimePrintContext context, StringBuilder buf) {
      Long value = context.getValue(field);
      if (value == null) {
        return false;
      }
      String text;
      Chronology chrono = context.getTemporal().query(TemporalQueries.chronology());
      if (chrono == null || chrono == IsoChronology.INSTANCE) {
        text = provider.getText(field, value, textStyle, context.getLocale());
      } else {
        text = provider.getText(chrono, field, value, textStyle, context.getLocale());
      }
      if (text == null) {
        return numberPrinterParser().format(context, buf);
      }
      buf.append(text);
      return true;
    }

    @Override
    public int parse(DateTimeParseContext context, CharSequence parseText, int position) {
      int length = parseText.length();
      if (position < 0 || position > length) {
        throw new IndexOutOfBoundsException();
      }
      TextStyle style = (context.isStrict() ? textStyle : null);
      Chronology chrono = context.getEffectiveChronology();
      Iterator<Entry<String, Long>> it;
      if (chrono == null || chrono == IsoChronology.INSTANCE) {
        it = provider.getTextIterator(field, style, context.getLocale());
      } else {
        it = provider.getTextIterator(chrono, field, style, context.getLocale());
      }
      if (it != null) {
        while (it.hasNext()) {
          Entry<String, Long> entry = it.next();
          String itText = entry.getKey();
          if (context.subSequenceEquals(itText, 0, parseText, position, itText.length())) {
            return context
                .setParsedField(field, entry.getValue(), position, position + itText.length());
          }
        }
        if (context.isStrict()) {
          return ~position;
        }
      }
      return numberPrinterParser().parse(context, parseText, position);
    }

    /**
     * Create and cache a number printer parser.
     *
     * @return the number printer parser for this field, not null
     */
    private NumberPrinterParser numberPrinterParser() {
      if (numberPrinterParser == null) {
        numberPrinterParser = new NumberPrinterParser(field, 1, 19, SignStyle.NORMAL);
      }
      return numberPrinterParser;
    }

    @Override
    public String toString() {
      if (textStyle == TextStyle.FULL) {
        return "Text(" + field + ")";
      }
      return "Text(" + field + "," + textStyle + ")";
    }
  }

  //-----------------------------------------------------------------------

  /**
   * Prints or parses an ISO-8601 instant.
   */
  static final class InstantPrinterParser implements DateTimePrinterParser {

    // days in a 400 year cycle = 146097
    // days in a 10,000 year cycle = 146097 * 25
    // seconds per day = 86400
    private static final long SECONDS_PER_10000_YEARS = 146097L * 25L * 86400L;
    private static final long SECONDS_0000_TO_1970 = ((146097L * 5L) - (30L * 365L + 7L)) * 86400L;
    private final int fractionalDigits;

    InstantPrinterParser(int fractionalDigits) {
      this.fractionalDigits = fractionalDigits;
    }

    @Override
    public boolean format(DateTimePrintContext context, StringBuilder buf) {
      // use INSTANT_SECONDS, thus this code is not bound by Instant.MAX
      Long inSecs = context.getValue(INSTANT_SECONDS);
      Long inNanos = null;
      if (context.getTemporal().isSupported(NANO_OF_SECOND)) {
        inNanos = context.getTemporal().getLong(NANO_OF_SECOND);
      }
      if (inSecs == null) {
        return false;
      }
      long inSec = inSecs;
      int inNano = NANO_OF_SECOND.checkValidIntValue(inNanos != null ? inNanos : 0);
      // format mostly using LocalDateTime.toString
      if (inSec >= -SECONDS_0000_TO_1970) {
        // current era
        long zeroSecs = inSec - SECONDS_PER_10000_YEARS + SECONDS_0000_TO_1970;
        long hi = Math.floorDiv(zeroSecs, SECONDS_PER_10000_YEARS) + 1;
        long lo = Math.floorMod(zeroSecs, SECONDS_PER_10000_YEARS);
        LocalDateTime ldt = LocalDateTime
            .ofEpochSecond(lo - SECONDS_0000_TO_1970, 0, ZoneOffset.UTC);
        if (hi > 0) {
          buf.append('+').append(hi);
        }
        buf.append(ldt);
        if (ldt.getSecond() == 0) {
          buf.append(":00");
        }
      } else {
        // before current era
        long zeroSecs = inSec + SECONDS_0000_TO_1970;
        long hi = zeroSecs / SECONDS_PER_10000_YEARS;
        long lo = zeroSecs % SECONDS_PER_10000_YEARS;
        LocalDateTime ldt = LocalDateTime
            .ofEpochSecond(lo - SECONDS_0000_TO_1970, 0, ZoneOffset.UTC);
        int pos = buf.length();
        buf.append(ldt);
        if (ldt.getSecond() == 0) {
          buf.append(":00");
        }
        if (hi < 0) {
          if (ldt.getYear() == -10_000) {
            buf.replace(pos, pos + 2, Long.toString(hi - 1));
          } else if (lo == 0) {
            buf.insert(pos, hi);
          } else {
            buf.insert(pos + 1, Math.abs(hi));
          }
        }
      }
      // add fraction
      if ((fractionalDigits < 0 && inNano > 0) || fractionalDigits > 0) {
        buf.append('.');
        int div = 100_000_000;
        for (int i = 0; ((fractionalDigits == -1 && inNano > 0) ||
            (fractionalDigits == -2 && (inNano > 0 || (i % 3) != 0)) ||
            i < fractionalDigits); i++) {
          int digit = inNano / div;
          buf.append((char) (digit + '0'));
          inNano = inNano - (digit * div);
          div = div / 10;
        }
      }
      buf.append('Z');
      return true;
    }

    @Override
    public int parse(DateTimeParseContext context, CharSequence text, int position) {
      // new context to avoid overwriting fields like year/month/day
      int minDigits = (fractionalDigits < 0 ? 0 : fractionalDigits);
      int maxDigits = (fractionalDigits < 0 ? 9 : fractionalDigits);
      CompositePrinterParser parser = new DateTimeFormatterBuilder()
          .append(DateTimeFormatter.ISO_LOCAL_DATE).appendLiteral('T')
          .appendValue(HOUR_OF_DAY, 2).appendLiteral(':')
          .appendValue(MINUTE_OF_HOUR, 2).appendLiteral(':')
          .appendValue(SECOND_OF_MINUTE, 2)
          .appendFraction(NANO_OF_SECOND, minDigits, maxDigits, true)
          .appendLiteral('Z')
          .toFormatter().toPrinterParser(false);
      DateTimeParseContext newContext = context.copy();
      int pos = parser.parse(newContext, text, position);
      if (pos < 0) {
        return pos;
      }
      // parser restricts most fields to 2 digits, so definitely int
      // correctly parsed nano is also guaranteed to be valid
      long yearParsed = newContext.getParsed(YEAR);
      int month = newContext.getParsed(MONTH_OF_YEAR).intValue();
      int day = newContext.getParsed(DAY_OF_MONTH).intValue();
      int hour = newContext.getParsed(HOUR_OF_DAY).intValue();
      int min = newContext.getParsed(MINUTE_OF_HOUR).intValue();
      Long secVal = newContext.getParsed(SECOND_OF_MINUTE);
      Long nanoVal = newContext.getParsed(NANO_OF_SECOND);
      int sec = (secVal != null ? secVal.intValue() : 0);
      int nano = (nanoVal != null ? nanoVal.intValue() : 0);
      int days = 0;
      if (hour == 24 && min == 0 && sec == 0 && nano == 0) {
        hour = 0;
        days = 1;
      } else if (hour == 23 && min == 59 && sec == 60) {
        context.setParsedLeapSecond();
        sec = 59;
      }
      int year = (int) yearParsed % 10_000;
      long instantSecs;
      try {
        LocalDateTime ldt = LocalDateTime.of(year, month, day, hour, min, sec, 0).plusDays(days);
        instantSecs = ldt.toEpochSecond(ZoneOffset.UTC);
        instantSecs += Math.multiplyExact(yearParsed / 10_000L, SECONDS_PER_10000_YEARS);
      } catch (RuntimeException ex) {
        return ~position;
      }
      int successPos = pos;
      successPos = context.setParsedField(INSTANT_SECONDS, instantSecs, position, successPos);
      return context.setParsedField(NANO_OF_SECOND, nano, position, successPos);
    }

    @Override
    public String toString() {
      return "Instant()";
    }
  }

  //-----------------------------------------------------------------------

  /**
   * Prints or parses an offset ID.
   */
  static final class OffsetIdPrinterParser implements DateTimePrinterParser {

    static final String[] PATTERNS = new String[]{
        "+HH", "+HHmm", "+HH:mm", "+HHMM", "+HH:MM", "+HHMMss", "+HH:MM:ss", "+HHMMSS", "+HH:MM:SS",
    };  // order used in pattern builder
    static final OffsetIdPrinterParser INSTANCE_ID_Z = new OffsetIdPrinterParser("+HH:MM:ss", "Z");
    static final OffsetIdPrinterParser INSTANCE_ID_ZERO = new OffsetIdPrinterParser("+HH:MM:ss",
        "0");

    private final String noOffsetText;
    private final int type;

    /**
     * Constructor.
     *
     * @param pattern the pattern
     * @param noOffsetText the text to use for UTC, not null
     */
    OffsetIdPrinterParser(String pattern, String noOffsetText) {
      Objects.requireNonNull(pattern, "pattern");
      Objects.requireNonNull(noOffsetText, "noOffsetText");
      this.type = checkPattern(pattern);
      this.noOffsetText = noOffsetText;
    }

    private int checkPattern(String pattern) {
      for (int i = 0; i < PATTERNS.length; i++) {
        if (PATTERNS[i].equals(pattern)) {
          return i;
        }
      }
      throw new IllegalArgumentException("Invalid zone offset pattern: " + pattern);
    }

    @Override
    public boolean format(DateTimePrintContext context, StringBuilder buf) {
      Long offsetSecs = context.getValue(OFFSET_SECONDS);
      if (offsetSecs == null) {
        return false;
      }
      int totalSecs = Math.toIntExact(offsetSecs);
      if (totalSecs == 0) {
        buf.append(noOffsetText);
      } else {
        int absHours = Math
            .abs((totalSecs / 3600) % 100);  // anything larger than 99 silently dropped
        int absMinutes = Math.abs((totalSecs / 60) % 60);
        int absSeconds = Math.abs(totalSecs % 60);
        int bufPos = buf.length();
        int output = absHours;
        buf.append(totalSecs < 0 ? "-" : "+")
            .append((char) (absHours / 10 + '0')).append((char) (absHours % 10 + '0'));
        if (type >= 3 || (type >= 1 && absMinutes > 0)) {
          buf.append((type % 2) == 0 ? ":" : "")
              .append((char) (absMinutes / 10 + '0')).append((char) (absMinutes % 10 + '0'));
          output += absMinutes;
          if (type >= 7 || (type >= 5 && absSeconds > 0)) {
            buf.append((type % 2) == 0 ? ":" : "")
                .append((char) (absSeconds / 10 + '0')).append((char) (absSeconds % 10 + '0'));
            output += absSeconds;
          }
        }
        if (output == 0) {
          buf.setLength(bufPos);
          buf.append(noOffsetText);
        }
      }
      return true;
    }

    @Override
    public int parse(DateTimeParseContext context, CharSequence text, int position) {
      int length = text.length();
      int noOffsetLen = noOffsetText.length();
      if (noOffsetLen == 0) {
        if (position == length) {
          return context.setParsedField(OFFSET_SECONDS, 0, position, position);
        }
      } else {
        if (position == length) {
          return ~position;
        }
        if (context.subSequenceEquals(text, position, noOffsetText, 0, noOffsetLen)) {
          return context.setParsedField(OFFSET_SECONDS, 0, position, position + noOffsetLen);
        }
      }

      // parse normal plus/minus offset
      char sign = text.charAt(position);  // IOOBE if invalid position
      if (sign == '+' || sign == '-') {
        // starts
        int negative = (sign == '-' ? -1 : 1);
        int[] array = new int[4];
        array[0] = position + 1;
        if ((parseNumber(array, 1, text, true) ||
            parseNumber(array, 2, text, type >= 3) ||
            parseNumber(array, 3, text, false)) == false) {
          // success
          long offsetSecs = negative * (array[1] * 3600L + array[2] * 60L + array[3]);
          return context.setParsedField(OFFSET_SECONDS, offsetSecs, position, array[0]);
        }
      }
      // handle special case of empty no offset text
      if (noOffsetLen == 0) {
        return context.setParsedField(OFFSET_SECONDS, 0, position, position + noOffsetLen);
      }
      return ~position;
    }

    /**
     * Parse a two digit zero-prefixed number.
     *
     * @param array the array of parsed data, 0=pos,1=hours,2=mins,3=secs, not null
     * @param arrayIndex the index to parse the value into
     * @param parseText the offset ID, not null
     * @param required whether this number is required
     * @return true if an error occurred
     */
    private boolean parseNumber(int[] array, int arrayIndex, CharSequence parseText,
        boolean required) {
      if ((type + 3) / 2 < arrayIndex) {
        return false;  // ignore seconds/minutes
      }
      int pos = array[0];
      if ((type % 2) == 0 && arrayIndex > 1) {
        if (pos + 1 > parseText.length() || parseText.charAt(pos) != ':') {
          return required;
        }
        pos++;
      }
      if (pos + 2 > parseText.length()) {
        return required;
      }
      char ch1 = parseText.charAt(pos++);
      char ch2 = parseText.charAt(pos++);
      if (ch1 < '0' || ch1 > '9' || ch2 < '0' || ch2 > '9') {
        return required;
      }
      int value = (ch1 - 48) * 10 + (ch2 - 48);
      if (value < 0 || value > 59) {
        return required;
      }
      array[arrayIndex] = value;
      array[0] = pos;
      return false;
    }

    @Override
    public String toString() {
      String converted = noOffsetText.replace("'", "''");
      return "Offset(" + PATTERNS[type] + ",'" + converted + "')";
    }
  }

  //-----------------------------------------------------------------------

  /**
   * Prints or parses an offset ID.
   */
  static final class LocalizedOffsetIdPrinterParser implements DateTimePrinterParser {

    private final TextStyle style;

    /**
     * Constructor.
     *
     * @param style the style, not null
     */
    LocalizedOffsetIdPrinterParser(TextStyle style) {
      this.style = style;
    }

    private static StringBuilder appendHMS(StringBuilder buf, int t) {
      return buf.append((char) (t / 10 + '0'))
          .append((char) (t % 10 + '0'));
    }

    @Override
    public boolean format(DateTimePrintContext context, StringBuilder buf) {
      Long offsetSecs = context.getValue(OFFSET_SECONDS);
      if (offsetSecs == null) {
        return false;
      }
      String gmtText = "GMT";  // TODO: get localized version of 'GMT'
      if (gmtText != null) {
        buf.append(gmtText);
      }
      int totalSecs = Math.toIntExact(offsetSecs);
      if (totalSecs != 0) {
        int absHours = Math
            .abs((totalSecs / 3600) % 100);  // anything larger than 99 silently dropped
        int absMinutes = Math.abs((totalSecs / 60) % 60);
        int absSeconds = Math.abs(totalSecs % 60);
        buf.append(totalSecs < 0 ? "-" : "+");
        if (style == TextStyle.FULL) {
          appendHMS(buf, absHours);
          buf.append(':');
          appendHMS(buf, absMinutes);
          if (absSeconds != 0) {
            buf.append(':');
            appendHMS(buf, absSeconds);
          }
        } else {
          if (absHours >= 10) {
            buf.append((char) (absHours / 10 + '0'));
          }
          buf.append((char) (absHours % 10 + '0'));
          if (absMinutes != 0 || absSeconds != 0) {
            buf.append(':');
            appendHMS(buf, absMinutes);
            if (absSeconds != 0) {
              buf.append(':');
              appendHMS(buf, absSeconds);
            }
          }
        }
      }
      return true;
    }

    int getDigit(CharSequence text, int position) {
      char c = text.charAt(position);
      if (c < '0' || c > '9') {
        return -1;
      }
      return c - '0';
    }

    @Override
    public int parse(DateTimeParseContext context, CharSequence text, int position) {
      int pos = position;
      int end = pos + text.length();
      String gmtText = "GMT";  // TODO: get localized version of 'GMT'
      if (gmtText != null) {
        if (!context.subSequenceEquals(text, pos, gmtText, 0, gmtText.length())) {
          return ~position;
        }
        pos += gmtText.length();
      }
      // parse normal plus/minus offset
      int negative = 0;
      if (pos == end) {
        return context.setParsedField(OFFSET_SECONDS, 0, position, pos);
      }
      char sign = text.charAt(pos);  // IOOBE if invalid position
      if (sign == '+') {
        negative = 1;
      } else if (sign == '-') {
        negative = -1;
      } else {
        return context.setParsedField(OFFSET_SECONDS, 0, position, pos);
      }
      pos++;
      int h = 0;
      int m = 0;
      int s = 0;
      if (style == TextStyle.FULL) {
        int h1 = getDigit(text, pos++);
        int h2 = getDigit(text, pos++);
        if (h1 < 0 || h2 < 0 || text.charAt(pos++) != ':') {
          return ~position;
        }
        h = h1 * 10 + h2;
        int m1 = getDigit(text, pos++);
        int m2 = getDigit(text, pos++);
        if (m1 < 0 || m2 < 0) {
          return ~position;
        }
        m = m1 * 10 + m2;
        if (pos + 2 < end && text.charAt(pos) == ':') {
          int s1 = getDigit(text, pos + 1);
          int s2 = getDigit(text, pos + 2);
          if (s1 >= 0 && s2 >= 0) {
            s = s1 * 10 + s2;
            pos += 3;
          }
        }
      } else {
        h = getDigit(text, pos++);
        if (h < 0) {
          return ~position;
        }
        if (pos < end) {
          int h2 = getDigit(text, pos);
          if (h2 >= 0) {
            h = h * 10 + h2;
            pos++;
          }
          if (pos + 2 < end && text.charAt(pos) == ':') {
            if (pos + 2 < end && text.charAt(pos) == ':') {
              int m1 = getDigit(text, pos + 1);
              int m2 = getDigit(text, pos + 2);
              if (m1 >= 0 && m2 >= 0) {
                m = m1 * 10 + m2;
                pos += 3;
                if (pos + 2 < end && text.charAt(pos) == ':') {
                  int s1 = getDigit(text, pos + 1);
                  int s2 = getDigit(text, pos + 2);
                  if (s1 >= 0 && s2 >= 0) {
                    s = s1 * 10 + s2;
                    pos += 3;
                  }
                }
              }
            }
          }
        }
      }
      long offsetSecs = negative * (h * 3600L + m * 60L + s);
      return context.setParsedField(OFFSET_SECONDS, offsetSecs, position, pos);
    }

    @Override
    public String toString() {
      return "LocalizedOffset(" + style + ")";
    }
  }

  //-----------------------------------------------------------------------

  /**
   * Prints or parses a zone ID.
   */
  static final class ZoneTextPrinterParser extends ZoneIdPrinterParser {

    /**
     * The text style to output.
     */
    private final TextStyle textStyle;

    /**
     * The preferred zoneid map
     */
    private Set<String> preferredZones;

    ZoneTextPrinterParser(TextStyle textStyle, Set<ZoneId> preferredZones) {
      super(TemporalQueries.zone(), "ZoneText(" + textStyle + ")");
      this.textStyle = Objects.requireNonNull(textStyle, "textStyle");
      if (preferredZones != null && preferredZones.size() != 0) {
        this.preferredZones = new HashSet<>();
        for (ZoneId id : preferredZones) {
          this.preferredZones.add(id.getId());
        }
      }
    }

    private static final int STD = 0;
    private static final int DST = 1;
    private static final int GENERIC = 2;
    private static final Map<String, SoftReference<Map<Locale, String[]>>> cache =
        new ConcurrentHashMap<>();

    private String getDisplayName(String id, int type, Locale locale) {
      if (textStyle == TextStyle.NARROW) {
        return null;
      }
      String[] names;
      SoftReference<Map<Locale, String[]>> ref = cache.get(id);
      Map<Locale, String[]> perLocale = null;
      if (ref == null || (perLocale = ref.get()) == null ||
          (names = perLocale.get(locale)) == null) {
        names = TimeZoneNameUtility.retrieveDisplayNames(id, locale);
        if (names == null) {
          return null;
        }
        names = Arrays.copyOfRange(names, 0, 7);
        names[5] =
            TimeZoneNameUtility.retrieveGenericDisplayName(id, TimeZone.LONG, locale);
        if (names[5] == null) {
          names[5] = names[0]; // use the id
        }
        names[6] =
            TimeZoneNameUtility.retrieveGenericDisplayName(id, TimeZone.SHORT, locale);
        if (names[6] == null) {
          names[6] = names[0];
        }
        if (perLocale == null) {
          perLocale = new ConcurrentHashMap<>();
        }
        perLocale.put(locale, names);
        cache.put(id, new SoftReference<>(perLocale));
      }
      switch (type) {
        case STD:
          return names[textStyle.zoneNameStyleIndex() + 1];
        case DST:
          return names[textStyle.zoneNameStyleIndex() + 3];
      }
      return names[textStyle.zoneNameStyleIndex() + 5];
    }

    @Override
    public boolean format(DateTimePrintContext context, StringBuilder buf) {
      ZoneId zone = context.getValue(TemporalQueries.zoneId());
      if (zone == null) {
        return false;
      }
      String zname = zone.getId();
      if (!(zone instanceof ZoneOffset)) {
        TemporalAccessor dt = context.getTemporal();
        String name = getDisplayName(zname,
            dt.isSupported(ChronoField.INSTANT_SECONDS)
                ? (zone.getRules().isDaylightSavings(Instant.from(dt)) ? DST : STD)
                : GENERIC,
            context.getLocale());
        if (name != null) {
          zname = name;
        }
      }
      buf.append(zname);
      return true;
    }

    // cache per instance for now
    private final Map<Locale, Entry<Integer, SoftReference<PrefixTree>>>
        cachedTree = new HashMap<>();
    private final Map<Locale, Entry<Integer, SoftReference<PrefixTree>>>
        cachedTreeCI = new HashMap<>();

    @Override
    protected PrefixTree getTree(DateTimeParseContext context) {
      if (textStyle == TextStyle.NARROW) {
        return super.getTree(context);
      }
      Locale locale = context.getLocale();
      boolean isCaseSensitive = context.isCaseSensitive();
      Set<String> regionIds = ZoneRulesProvider.getAvailableZoneIds();
      int regionIdsSize = regionIds.size();

      Map<Locale, Entry<Integer, SoftReference<PrefixTree>>> cached =
          isCaseSensitive ? cachedTree : cachedTreeCI;

      Entry<Integer, SoftReference<PrefixTree>> entry = null;
      PrefixTree tree = null;
      String[][] zoneStrings = null;
      if ((entry = cached.get(locale)) == null ||
          (entry.getKey() != regionIdsSize ||
              (tree = entry.getValue().get()) == null)) {
        tree = PrefixTree.newTree(context);
        zoneStrings = TimeZoneNameUtility.getZoneStrings(locale);
        for (String[] names : zoneStrings) {
          String zid = names[0];
          if (!regionIds.contains(zid)) {
            continue;
          }
          tree.add(zid, zid);    // don't convert zid -> metazone
          zid = ZoneName.toZid(zid, locale);
          int i = textStyle == TextStyle.FULL ? 1 : 2;
          for (; i < names.length; i += 2) {
            tree.add(names[i], zid);
          }
        }
        // if we have a set of preferred zones, need a copy and
        // add the preferred zones again to overwrite
        if (preferredZones != null) {
          for (String[] names : zoneStrings) {
            String zid = names[0];
            if (!preferredZones.contains(zid) || !regionIds.contains(zid)) {
              continue;
            }
            int i = textStyle == TextStyle.FULL ? 1 : 2;
            for (; i < names.length; i += 2) {
              tree.add(names[i], zid);
            }
          }
        }
        cached.put(locale, new SimpleImmutableEntry<>(regionIdsSize, new SoftReference<>(tree)));
      }
      return tree;
    }
  }

  //-----------------------------------------------------------------------

  /**
   * Prints or parses a zone ID.
   */
  static class ZoneIdPrinterParser implements DateTimePrinterParser {

    private final TemporalQuery<ZoneId> query;
    private final String description;

    ZoneIdPrinterParser(TemporalQuery<ZoneId> query, String description) {
      this.query = query;
      this.description = description;
    }

    @Override
    public boolean format(DateTimePrintContext context, StringBuilder buf) {
      ZoneId zone = context.getValue(query);
      if (zone == null) {
        return false;
      }
      buf.append(zone.getId());
      return true;
    }

    /**
     * The cached tree to speed up parsing.
     */
    private static volatile Entry<Integer, PrefixTree> cachedPrefixTree;
    private static volatile Entry<Integer, PrefixTree> cachedPrefixTreeCI;

    protected PrefixTree getTree(DateTimeParseContext context) {
      // prepare parse tree
      Set<String> regionIds = ZoneRulesProvider.getAvailableZoneIds();
      final int regionIdsSize = regionIds.size();
      Entry<Integer, PrefixTree> cached = context.isCaseSensitive()
          ? cachedPrefixTree : cachedPrefixTreeCI;
      if (cached == null || cached.getKey() != regionIdsSize) {
        synchronized (this) {
          cached = context.isCaseSensitive() ? cachedPrefixTree : cachedPrefixTreeCI;
          if (cached == null || cached.getKey() != regionIdsSize) {
            cached = new SimpleImmutableEntry<>(regionIdsSize,
                PrefixTree.newTree(regionIds, context));
            if (context.isCaseSensitive()) {
              cachedPrefixTree = cached;
            } else {
              cachedPrefixTreeCI = cached;
            }
          }
        }
      }
      return cached.getValue();
    }

    /**
     * This implementation looks for the longest matching string.
     * For example, parsing Etc/GMT-2 will return Etc/GMC-2 rather than just
     * Etc/GMC although both are valid.
     */
    @Override
    public int parse(DateTimeParseContext context, CharSequence text, int position) {
      int length = text.length();
      if (position > length) {
        throw new IndexOutOfBoundsException();
      }
      if (position == length) {
        return ~position;
      }

      // handle fixed time-zone IDs
      char nextChar = text.charAt(position);
      if (nextChar == '+' || nextChar == '-') {
        return parseOffsetBased(context, text, position, position,
            OffsetIdPrinterParser.INSTANCE_ID_Z);
      } else if (length >= position + 2) {
        char nextNextChar = text.charAt(position + 1);
        if (context.charEquals(nextChar, 'U') && context.charEquals(nextNextChar, 'T')) {
          if (length >= position + 3 && context.charEquals(text.charAt(position + 2), 'C')) {
            return parseOffsetBased(context, text, position, position + 3,
                OffsetIdPrinterParser.INSTANCE_ID_ZERO);
          }
          return parseOffsetBased(context, text, position, position + 2,
              OffsetIdPrinterParser.INSTANCE_ID_ZERO);
        } else if (context.charEquals(nextChar, 'G') && length >= position + 3 &&
            context.charEquals(nextNextChar, 'M') && context
            .charEquals(text.charAt(position + 2), 'T')) {
          return parseOffsetBased(context, text, position, position + 3,
              OffsetIdPrinterParser.INSTANCE_ID_ZERO);
        }
      }

      // parse
      PrefixTree tree = getTree(context);
      ParsePosition ppos = new ParsePosition(position);
      String parsedZoneId = tree.match(text, ppos);
      if (parsedZoneId == null) {
        if (context.charEquals(nextChar, 'Z')) {
          context.setParsed(ZoneOffset.UTC);
          return position + 1;
        }
        return ~position;
      }
      context.setParsed(ZoneId.of(parsedZoneId));
      return ppos.getIndex();
    }

    /**
     * Parse an offset following a prefix and set the ZoneId if it is valid.
     * To matching the parsing of ZoneId.of the values are not normalized
     * to ZoneOffsets.
     *
     * @param context the parse context
     * @param text the input text
     * @param prefixPos start of the prefix
     * @param position start of text after the prefix
     * @param parser parser for the value after the prefix
     * @return the position after the parse
     */
    private int parseOffsetBased(DateTimeParseContext context, CharSequence text, int prefixPos,
        int position, OffsetIdPrinterParser parser) {
      String prefix = text.toString().substring(prefixPos, position).toUpperCase();
      if (position >= text.length()) {
        context.setParsed(ZoneId.of(prefix));
        return position;
      }

      // '0' or 'Z' after prefix is not part of a valid ZoneId; use bare prefix
      if (text.charAt(position) == '0' ||
          context.charEquals(text.charAt(position), 'Z')) {
        context.setParsed(ZoneId.of(prefix));
        return position;
      }

      DateTimeParseContext newContext = context.copy();
      int endPos = parser.parse(newContext, text, position);
      try {
        if (endPos < 0) {
          if (parser == OffsetIdPrinterParser.INSTANCE_ID_Z) {
            return ~prefixPos;
          }
          context.setParsed(ZoneId.of(prefix));
          return position;
        }
        int offset = (int) newContext.getParsed(OFFSET_SECONDS).longValue();
        ZoneOffset zoneOffset = ZoneOffset.ofTotalSeconds(offset);
        context.setParsed(ZoneId.ofOffset(prefix, zoneOffset));
        return endPos;
      } catch (DateTimeException dte) {
        return ~prefixPos;
      }
    }

    @Override
    public String toString() {
      return description;
    }
  }

  //-----------------------------------------------------------------------

  /**
   * A String based prefix tree for parsing time-zone names.
   */
  static class PrefixTree {

    protected String key;
    protected String value;
    protected char c0;    // performance optimization to avoid the
    // boundary check cost of key.charat(0)
    protected PrefixTree child;
    protected PrefixTree sibling;

    private PrefixTree(String k, String v, PrefixTree child) {
      this.key = k;
      this.value = v;
      this.child = child;
      if (k.length() == 0) {
        c0 = 0xffff;
      } else {
        c0 = key.charAt(0);
      }
    }

    /**
     * Creates a new prefix parsing tree based on parse context.
     *
     * @param context the parse context
     * @return the tree, not null
     */
    public static PrefixTree newTree(DateTimeParseContext context) {
      //if (!context.isStrict()) {
      //    return new LENIENT("", null, null);
      //}
      if (context.isCaseSensitive()) {
        return new PrefixTree("", null, null);
      }
      return new CI("", null, null);
    }

    /**
     * Creates a new prefix parsing tree.
     *
     * @param keys a set of strings to build the prefix parsing tree, not null
     * @param context the parse context
     * @return the tree, not null
     */
    public static PrefixTree newTree(Set<String> keys, DateTimeParseContext context) {
      PrefixTree tree = newTree(context);
      for (String k : keys) {
        tree.add0(k, k);
      }
      return tree;
    }

    /**
     * Clone a copy of this tree
     */
    public PrefixTree copyTree() {
      PrefixTree copy = new PrefixTree(key, value, null);
      if (child != null) {
        copy.child = child.copyTree();
      }
      if (sibling != null) {
        copy.sibling = sibling.copyTree();
      }
      return copy;
    }


    /**
     * Adds a pair of {key, value} into the prefix tree.
     *
     * @param k the key, not null
     * @param v the value, not null
     * @return true if the pair is added successfully
     */
    public boolean add(String k, String v) {
      return add0(k, v);
    }

    private boolean add0(String k, String v) {
      k = toKey(k);
      int prefixLen = prefixLength(k);
      if (prefixLen == key.length()) {
        if (prefixLen < k.length()) {  // down the tree
          String subKey = k.substring(prefixLen);
          PrefixTree c = child;
          while (c != null) {
            if (isEqual(c.c0, subKey.charAt(0))) {
              return c.add0(subKey, v);
            }
            c = c.sibling;
          }
          // add the node as the child of the current node
          c = newNode(subKey, v, null);
          c.sibling = child;
          child = c;
          return true;
        }
        // have an existing <key, value> already, overwrite it
        // if (value != null) {
        //    return false;
        //}
        value = v;
        return true;
      }
      // split the existing node
      PrefixTree n1 = newNode(key.substring(prefixLen), value, child);
      key = k.substring(0, prefixLen);
      child = n1;
      if (prefixLen < k.length()) {
        PrefixTree n2 = newNode(k.substring(prefixLen), v, null);
        child.sibling = n2;
        value = null;
      } else {
        value = v;
      }
      return true;
    }

    /**
     * Match text with the prefix tree.
     *
     * @param text the input text to parse, not null
     * @param off the offset position to start parsing at
     * @param end the end position to stop parsing
     * @return the resulting string, or null if no match found.
     */
    public String match(CharSequence text, int off, int end) {
      if (!prefixOf(text, off, end)) {
        return null;
      }
      if (child != null && (off += key.length()) != end) {
        PrefixTree c = child;
        do {
          if (isEqual(c.c0, text.charAt(off))) {
            String found = c.match(text, off, end);
            if (found != null) {
              return found;
            }
            return value;
          }
          c = c.sibling;
        } while (c != null);
      }
      return value;
    }

    /**
     * Match text with the prefix tree.
     *
     * @param text the input text to parse, not null
     * @param pos the position to start parsing at, from 0 to the text length. Upon return, position
     * will be updated to the new parse position, or unchanged, if no match found.
     * @return the resulting string, or null if no match found.
     */
    public String match(CharSequence text, ParsePosition pos) {
      int off = pos.getIndex();
      int end = text.length();
      if (!prefixOf(text, off, end)) {
        return null;
      }
      off += key.length();
      if (child != null && off != end) {
        PrefixTree c = child;
        do {
          if (isEqual(c.c0, text.charAt(off))) {
            pos.setIndex(off);
            String found = c.match(text, pos);
            if (found != null) {
              return found;
            }
            break;
          }
          c = c.sibling;
        } while (c != null);
      }
      pos.setIndex(off);
      return value;
    }

    protected String toKey(String k) {
      return k;
    }

    protected PrefixTree newNode(String k, String v, PrefixTree child) {
      return new PrefixTree(k, v, child);
    }

    protected boolean isEqual(char c1, char c2) {
      return c1 == c2;
    }

    protected boolean prefixOf(CharSequence text, int off, int end) {
      if (text instanceof String) {
        return ((String) text).startsWith(key, off);
      }
      int len = key.length();
      if (len > end - off) {
        return false;
      }
      int off0 = 0;
      while (len-- > 0) {
        if (!isEqual(key.charAt(off0++), text.charAt(off++))) {
          return false;
        }
      }
      return true;
    }

    private int prefixLength(String k) {
      int off = 0;
      while (off < k.length() && off < key.length()) {
        if (!isEqual(k.charAt(off), key.charAt(off))) {
          return off;
        }
        off++;
      }
      return off;
    }

    /**
     * Case Insensitive prefix tree.
     */
    private static class CI extends PrefixTree {

      private CI(String k, String v, PrefixTree child) {
        super(k, v, child);
      }

      @Override
      protected CI newNode(String k, String v, PrefixTree child) {
        return new CI(k, v, child);
      }

      @Override
      protected boolean isEqual(char c1, char c2) {
        return DateTimeParseContext.charEqualsIgnoreCase(c1, c2);
      }

      @Override
      protected boolean prefixOf(CharSequence text, int off, int end) {
        int len = key.length();
        if (len > end - off) {
          return false;
        }
        int off0 = 0;
        while (len-- > 0) {
          if (!isEqual(key.charAt(off0++), text.charAt(off++))) {
            return false;
          }
        }
        return true;
      }
    }

    /**
     * Lenient prefix tree. Case insensitive and ignores characters
     * like space, underscore and slash.
     */
    private static class LENIENT extends CI {

      private LENIENT(String k, String v, PrefixTree child) {
        super(k, v, child);
      }

      @Override
      protected CI newNode(String k, String v, PrefixTree child) {
        return new LENIENT(k, v, child);
      }

      private boolean isLenientChar(char c) {
        return c == ' ' || c == '_' || c == '/';
      }

      protected String toKey(String k) {
        for (int i = 0; i < k.length(); i++) {
          if (isLenientChar(k.charAt(i))) {
            StringBuilder sb = new StringBuilder(k.length());
            sb.append(k, 0, i);
            i++;
            while (i < k.length()) {
              if (!isLenientChar(k.charAt(i))) {
                sb.append(k.charAt(i));
              }
              i++;
            }
            return sb.toString();
          }
        }
        return k;
      }

      @Override
      public String match(CharSequence text, ParsePosition pos) {
        int off = pos.getIndex();
        int end = text.length();
        int len = key.length();
        int koff = 0;
        while (koff < len && off < end) {
          if (isLenientChar(text.charAt(off))) {
            off++;
            continue;
          }
          if (!isEqual(key.charAt(koff++), text.charAt(off++))) {
            return null;
          }
        }
        if (koff != len) {
          return null;
        }
        if (child != null && off != end) {
          int off0 = off;
          while (off0 < end && isLenientChar(text.charAt(off0))) {
            off0++;
          }
          if (off0 < end) {
            PrefixTree c = child;
            do {
              if (isEqual(c.c0, text.charAt(off0))) {
                pos.setIndex(off0);
                String found = c.match(text, pos);
                if (found != null) {
                  return found;
                }
                break;
              }
              c = c.sibling;
            } while (c != null);
          }
        }
        pos.setIndex(off);
        return value;
      }
    }
  }

  //-----------------------------------------------------------------------

  /**
   * Prints or parses a chronology.
   */
  static final class ChronoPrinterParser implements DateTimePrinterParser {

    /**
     * The text style to output, null means the ID.
     */
    private final TextStyle textStyle;

    ChronoPrinterParser(TextStyle textStyle) {
      // validated by caller
      this.textStyle = textStyle;
    }

    @Override
    public boolean format(DateTimePrintContext context, StringBuilder buf) {
      Chronology chrono = context.getValue(TemporalQueries.chronology());
      if (chrono == null) {
        return false;
      }
      if (textStyle == null) {
        buf.append(chrono.getId());
      } else {
        buf.append(getChronologyName(chrono, context.getLocale()));
      }
      return true;
    }

    @Override
    public int parse(DateTimeParseContext context, CharSequence text, int position) {
      // simple looping parser to find the chronology
      if (position < 0 || position > text.length()) {
        throw new IndexOutOfBoundsException();
      }
      Set<Chronology> chronos = Chronology.getAvailableChronologies();
      Chronology bestMatch = null;
      int matchLen = -1;
      for (Chronology chrono : chronos) {
        String name;
        if (textStyle == null) {
          name = chrono.getId();
        } else {
          name = getChronologyName(chrono, context.getLocale());
        }
        int nameLen = name.length();
        if (nameLen > matchLen && context.subSequenceEquals(text, position, name, 0, nameLen)) {
          bestMatch = chrono;
          matchLen = nameLen;
        }
      }
      if (bestMatch == null) {
        return ~position;
      }
      context.setParsed(bestMatch);
      return position + matchLen;
    }

    /**
     * Returns the chronology name of the given chrono in the given locale
     * if available, or the chronology Id otherwise. The regular ResourceBundle
     * search path is used for looking up the chronology name.
     *
     * @param chrono the chronology, not null
     * @param locale the locale, not null
     * @return the chronology name of chrono in locale, or the id if no name is available
     * @throws NullPointerException if chrono or locale is null
     */
    private String getChronologyName(Chronology chrono, Locale locale) {
      String key = "calendarname." + chrono.getCalendarType();
      String name = DateTimeTextProvider.getLocalizedResource(key, locale);
      return name != null ? name : chrono.getId();
    }
  }

  //-----------------------------------------------------------------------

  /**
   * Prints or parses a localized pattern.
   */
  static final class LocalizedPrinterParser implements DateTimePrinterParser {

    /**
     * Cache of formatters.
     */
    private static final ConcurrentMap<String, DateTimeFormatter> FORMATTER_CACHE = new ConcurrentHashMap<>(
        16, 0.75f, 2);

    private final FormatStyle dateStyle;
    private final FormatStyle timeStyle;

    /**
     * Constructor.
     *
     * @param dateStyle the date style to use, may be null
     * @param timeStyle the time style to use, may be null
     */
    LocalizedPrinterParser(FormatStyle dateStyle, FormatStyle timeStyle) {
      // validated by caller
      this.dateStyle = dateStyle;
      this.timeStyle = timeStyle;
    }

    @Override
    public boolean format(DateTimePrintContext context, StringBuilder buf) {
      Chronology chrono = Chronology.from(context.getTemporal());
      return formatter(context.getLocale(), chrono).toPrinterParser(false).format(context, buf);
    }

    @Override
    public int parse(DateTimeParseContext context, CharSequence text, int position) {
      Chronology chrono = context.getEffectiveChronology();
      return formatter(context.getLocale(), chrono).toPrinterParser(false)
          .parse(context, text, position);
    }

    /**
     * Gets the formatter to use.
     * <p>
     * The formatter will be the most appropriate to use for the date and time style in the locale.
     * For example, some locales will use the month name while others will use the number.
     *
     * @param locale the locale to use, not null
     * @param chrono the chronology to use, not null
     * @return the formatter, not null
     * @throws IllegalArgumentException if the formatter cannot be found
     */
    private DateTimeFormatter formatter(Locale locale, Chronology chrono) {
      String key = chrono.getId() + '|' + locale.toString() + '|' + dateStyle + timeStyle;
      DateTimeFormatter formatter = FORMATTER_CACHE.get(key);
      if (formatter == null) {
        String pattern = getLocalizedDateTimePattern(dateStyle, timeStyle, chrono, locale);
        formatter = new DateTimeFormatterBuilder().appendPattern(pattern).toFormatter(locale);
        DateTimeFormatter old = FORMATTER_CACHE.putIfAbsent(key, formatter);
        if (old != null) {
          formatter = old;
        }
      }
      return formatter;
    }

    @Override
    public String toString() {
      return "Localized(" + (dateStyle != null ? dateStyle : "") + "," +
          (timeStyle != null ? timeStyle : "") + ")";
    }
  }

  //-----------------------------------------------------------------------

  /**
   * Prints or parses a localized pattern from a localized field.
   * The specific formatter and parameters is not selected until the
   * the field is to be printed or parsed.
   * The locale is needed to select the proper WeekFields from which
   * the field for day-of-week, week-of-month, or week-of-year is selected.
   */
  static final class WeekBasedFieldPrinterParser implements DateTimePrinterParser {

    private char chr;
    private int count;

    /**
     * Constructor.
     *
     * @param chr the pattern format letter that added this PrinterParser.
     * @param count the repeat count of the format letter
     */
    WeekBasedFieldPrinterParser(char chr, int count) {
      this.chr = chr;
      this.count = count;
    }

    @Override
    public boolean format(DateTimePrintContext context, StringBuilder buf) {
      return printerParser(context.getLocale()).format(context, buf);
    }

    @Override
    public int parse(DateTimeParseContext context, CharSequence text, int position) {
      return printerParser(context.getLocale()).parse(context, text, position);
    }

    /**
     * Gets the printerParser to use based on the field and the locale.
     *
     * @param locale the locale to use, not null
     * @return the formatter, not null
     * @throws IllegalArgumentException if the formatter cannot be found
     */
    private DateTimePrinterParser printerParser(Locale locale) {
      WeekFields weekDef = WeekFields.of(locale);
      TemporalField field = null;
      switch (chr) {
        case 'Y':
          field = weekDef.weekBasedYear();
          if (count == 2) {
            return new ReducedPrinterParser(field, 2, 2, 0, ReducedPrinterParser.BASE_DATE, 0);
          } else {
            return new NumberPrinterParser(field, count, 19,
                (count < 4) ? SignStyle.NORMAL : SignStyle.EXCEEDS_PAD, -1);
          }
        case 'e':
        case 'c':
          field = weekDef.dayOfWeek();
          break;
        case 'w':
          field = weekDef.weekOfWeekBasedYear();
          break;
        case 'W':
          field = weekDef.weekOfMonth();
          break;
        default:
          throw new IllegalStateException("unreachable");
      }
      return new NumberPrinterParser(field, (count == 2 ? 2 : 1), 2, SignStyle.NOT_NEGATIVE);
    }

    @Override
    public String toString() {
      StringBuilder sb = new StringBuilder(30);
      sb.append("Localized(");
      if (chr == 'Y') {
        if (count == 1) {
          sb.append("WeekBasedYear");
        } else if (count == 2) {
          sb.append("ReducedValue(WeekBasedYear,2,2,2000-01-01)");
        } else {
          sb.append("WeekBasedYear,").append(count).append(",")
              .append(19).append(",")
              .append((count < 4) ? SignStyle.NORMAL : SignStyle.EXCEEDS_PAD);
        }
      } else {
        switch (chr) {
          case 'c':
          case 'e':
            sb.append("DayOfWeek");
            break;
          case 'w':
            sb.append("WeekOfWeekBasedYear");
            break;
          case 'W':
            sb.append("WeekOfMonth");
            break;
          default:
            break;
        }
        sb.append(",");
        sb.append(count);
      }
      sb.append(")");
      return sb.toString();
    }
  }

  //-------------------------------------------------------------------------
  /**
   * Length comparator.
   */
  static final Comparator<String> LENGTH_SORT = new Comparator<String>() {
    @Override
    public int compare(String str1, String str2) {
      return str1.length() == str2.length() ? str1.compareTo(str2) : str1.length() - str2.length();
    }
  };
}
